Find synonym:
They can enjoy the -comfort and elegance of five-star hotels and luxury cruise ships.

 

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If I ________ that Brian had to get up early, I would have woken him up.

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Adolescence is the period ________ child and young adulthood

BODY LANGUAGE AND CULTURAL DIFFERENCES
The body language people use often communicates more about their feelings than the words they are saying. We use body movements, hand gestures, facial expressions, and changes in our voice to communicate with each other. Although some body language is universal, many gestures are culturally specific and may mean different things in different countries. 
If you want to give someone the nod in Bulgaria, you have to nod your head to say no and shake it to say yes – the exact opposite of what we do! In Belgium, pointing with your index finger or snapping your fingers at someone is very rude. 
In France, you shouldn't rest your feet on tables or chairs. Speaking to someone with your hands in your pockets will only make matters worse. In the Middle East, you should never show the soles of your feet or shoes to others as it will be seen as a grave insult. When eating, only use your right hand because they use their left hands when going to the bathroom. 
In Bangladesh, the 'thumbs-up' is a rude sign. In Myanmar, people greet each other by clapping, and in India, whistling in public is considered rude.
In Japan, you should not blow your nose in public, but you can burp at the end of a meal to show that you have enjoyed it. The 'OK' sign (thumb and index finger forming a circle) means 'everything is good' in the West, but in China it means nothing or zero. In Japan, it means money, and in the Middle East, it is a rude gesture.

The word “others” in paragraph 3 refers to __________.

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The first two decades of this century were dominated by the microbe hunters. These hunters had tracked down one after another of the microbes responsible for the most dreaded scourges of many centuries: tuberculosis, cholera, diphtheria. But there remained some terrible diseases for which no microbe could be incriminated: scurvy, pellagra, rickets, beriberi. Then it was discovered that these diseases were caused by the lack of vitamins, a trace substance in the diet. The diseases could be prevented or cured by consuming foods that contained the vitamins. And so in the decades of the 1920’s and 1930’s, nutrition became a science and the vitamin hunters replaced the microbe hunters. In the 1940’s and 1950’s, biochemists strived to learn why each of the vitamins was essential for health. They discovered that key enzymes in metabolism depend on one or another of the vitamins as coenzymes to perform the chemistry that provides cells with energy for growth and function. Now, these enzyme hunters occupied center stage. You are aware that the enzyme hunters have been replaced by a new breed of hunters who are tracking genes – the blueprints for each of the enzymes – and are discovering the defective genes that cause inherited diseases – diabetes, cystic fibrosis. These gene hunters, or genetic engineers, use recombinant DNA technology to identify and clone genes and introduce them into bacterial cells and plants to create factories for the massive production of hormones and vaccines for medicine and for better crops for agriculture. Biotechnology has become a multibilliondollar industry. In view of the inexorable progress in science, we can expect that the gene hunters will be replaced in the spotlight. When and by whom? Which kind of hunter will dominate the scene in the last decade of our waning century and in the early decades of the next? I wonder whether the hunters who will occupy the spotlight will be neurobiologists who apply the techniques of the enzyme and gene hunters to the funtions of the brain. What to call them? The head hunters. I will return to them later.
3. Which of the following can be cured by a change in diet?

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The Internet is very much like television, in which it takes time away from other pursuits, provides entertainment and information, but in no way can compare with the warm, personal experience of reading a good book. This is not the only reason why the Internet will never replace books, for books provide the in-depth knowledge of a subject that sitting in front of a computer monitor cannot provide. We can download text from an Internet source, but the aesthetic quality of sheets of downloaded text leave much to be desired. A welldesigned book enhances the reading experience. The book is still the most compact and inexpensive means of conveying a dense amount of knowledge in a convenient package. The easy portability of the book is what makes it the most user-friendly format for knowledge ever invented. The idea that one can carry in one’s pocket a play by Shakespeare, a novel by Charles Dickens or Tom Clancy, Plato’s Dialogues, or the Bible in a small paperback edition is mind-boggling. We take such uncommon convenience for granted, not realizing that the book itself has undergone quite an evolution since the production of the Gutenberg Bible in 1455 and Shakespeare’s First Folio in 1623, just three years after the Pilgrims landed at Plymouth to colonize the New World. Not only has the art and craft of printing and book manufacturing been greatly improved over the centuries, but the great variety of subject matter now available in books is astounding, to say the least. In fact, the Internet requires the constant input of authors and their books to provide it with the information that makes it a useful tool for exploration and learning.  Another important reason why the Internet will never replace books is because those who wish to become writers want to see their works permanently published as books - something you can hold, see, feel, skim through, and read at one’s leisure without the need for an electric current apart from a lamp. The writer may use a word processor instead of a typewriter or a pen and pad, but the finished product must eventually end up as a book if it is to have value to the reading public. The writer may use the Internet in the course of researching a subject just as he may use a library for that purpose, but the end product will still be a book.
7. According to the passage, which sentence is NOT true about books?

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In today’s fast-paced industry, learning will most likely involve seeking new skills in ways that challenge the norm. But thankfully, there is a promise for such lifelong learning online - the promise that will save your time and money while helping you earn more of both. Provided you have access to a decent computer and the Internet, the barrier to getting started is probably lower than it ever has been. And with those things in place, it is a matter of finding the content you wish to learn. So, to help others who may be looking to maximize their own learning efforts, I have listed some quick tips below. First, set achievable goals. When you start learning, it is a good idea to set goals about what you want to learn or what you might do with your newly acquired knowledge. It might be landing that new job, building a tangible product, or impressing your current management. The goals may vary in size and complexity, but do revisit these goals throughout your learning process. Within a couple weeks, ask yourself: “Am I getting closer to my goal?” or “Am I learning the skills necessary to reach my goals?”. If you are not, then you may need to look elsewhere. Second, learn with others. By yourself, learning anything has a high propensity to become frustrating. Try teaming up with friends or colleagues. They can often be your best resource for maintaining motivation while you learn. Third, make it a habit. Online habits often include scrolling through social media or watching videos on YouTube. If you have the downtime for such activities, then you could spend that downtime learning something. And why not learn something? If you do, then you will have plenty more to talk about on social media anyways. So, make learning your new online habit by making a commitment to learn something new each day. 
1. According to the passage, what are the basic conditions for learning online? 

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Scientists have uncovered a new threat to the world’s endangered coral reefs. They  have found that most are incapable of growing quickly enough to compensate for rising sea levels triggered by global warming. The study suggests that reefs – which are already suffering serious degradation because the world’s seas are warming and becoming more acidic – could also become overwhelmed by rising oceans.  The research – led by scientists at Exeter University and published in Nature this week – involved studying growth rates for more than 200 tropical western Atlantic and Indian Ocean reefs. It was found only 9% of these reefs had the ability to keep up with even the most optimistic rates of sea-level rises forecast by the Intergovernmental Panel on Climate Change. “For many reefs across the Caribbean and Indian Ocean regions, where the study focused, rates of growth are slowing due to coral reef degradation,” said Professor Chris Perry, of Exeter University. “Meanwhile, rates of sea-level rise are increasing – and our results suggest reefs will be unable to keep up. As a result, water depths above most reefs will increase rapidly through this century.”  Sea levels rose by several inches over the past century and measurements indicate the speed of this increase is now rising significantly. Two key factors are involved: climate change is making ocean water warmer and so it expands. And as ice sheets and glaciers melt, they increase amounts of water in the oceans.  At the same time, reefs are being weakened by ocean warming and also by ocean acidification, triggered as the seas absorb more and more carbon dioxide. These effects lead to bleaching events that kill off vast stretches of coral and limits their ability to grow.  “Our predictions, even under the best case scenarios, suggest that by 2100, the inundation of reefs will expose coastal communities to significant threats of shoreline change,” said co-author Prof Peter Mumby of Queensland University. This point was backed by US marine scientist Ilsa Kuffner writing in a separate comment piece for Nature. “The implications of the study are dire. Many island nations and territories are set to quickly lose crucial natural resources.” 
2. What does the word “compensate” in the first paragraph probably mean?

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Whether a species is endangered—meaning at risk of extinction—depends on which definition you use. The International Union for Conservation of Nature’s Red List of Threatened Species classifies an animal as endangered when its numbers in the wild have dropped so low that it’s at “extremely high risk” of extinction. Meanwhile, the United States’ Endangered Species Act of 1973 takes into consideration any destruction to a species’ habitat, whether it has been over-consumed, any disease or predation that threaten it, whether any other man-made factors put it in danger, and what policies currently exist to protect it. When members of the public or a state agency propose to the U.S. Fish & Wildlife Service or the National Marine Fisheries Service that a species be listed as endangered under the law, research and management plans are formed to help those species survive. It is illegal under the Endangered Species Act to capture, hunt, shoot, or otherwise harm an animal that’s listed as endangered. Sometimes, federal agencies decide that although a species could be considered endangered, other species are higher priorities. In those cases, the animal or plant gets limited protections. One animal whose numbers have increased through conservation is the bald eagle. There were only about 500 bald eagles in the continental United States in the 1960s because of pesticides that damaged the shells of their eggs. Conservation efforts including captive breeding programs, habitat protection, and a ban on the insecticide DDT helped the bald eagle’s numbers soar back into the thousands. Another is the giant panda, which was declared no longer endangered in 2016 thanks to 50 years of efforts to save it. U.S. Rep. John Dingell, who wrote the Endangered Species Act, argued that “only natural extinction is part of natural order.” Scientists believe that 227 species - including the grizzly bear, the peregrine falcon and the gray wolf - were saved from extinction in the first 33 years of the law’s existence. Still, critics argue that the act is expensive and ineffective because it protects so many species. Several federal courts have heard and rejected arguments that the Endangered Species Act is unconstitutional, and members of Congress have tried to weaken the law in small ways.
4. According to paragraph 2, what can happen to the species filed under the endangered list?

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A new study shows that urbanization shifts this seasonal cue in nuanced ways, with cities in cold climates triggering earlier spring plant growth and cities in warm climates delaying it. The study also found that the urban heat island effect, the phenomenon in which cities are warmer than their surroundings, is not the only culprit behind the shift, suggesting that other aspects of urbanization, such as pollution, changes in humidity and fertilizer runoff, may also influence plants’ seasonal patterns.  Researchers analyzed millions of observations of 136 plant species across the U.S. and Europe to study how regional temperature and the local density of people-a proxy for urbanization—affect when plants sprout leaves and blossoms. Their results revealed a complex story: Separately, warmer temperatures and higher population density each spurred earlier springs. A 3.6-degree Fahrenheit increase in temperature bumped up plants’ production of leaves and flowers by about five and six days, respectively. A fourfold increase in human population density advanced flowering and leaf production dates by about three days. But the team found that when these two factors worked together, local temperature had an outsized influence. In cold regions—areas with an average November-to-May temperature of about 18 degrees-plants produced leaves and flowers about 20 days earlier in locations with about 26,000 people per square mile, compared with equally frigid wildland. When an area’s average November-to-May temperature jumped to 68, however, leaves and flowers appeared four and six days later, respectively, in locations with about 26,000 people per square mile, compared with equally balmy wildland. In New York, for example, plants are likely sprouting leaves about 9.5 days earlier and blossoms eight days earlier than uninhabited regions with the same temperature. Jacksonville, in contrast, is likely pushing leaf production later by about one day and flowers by about half a day, with leaves appearing two days later and flowers a day later in Houston.  Even after accounting for urban heat islands, the team’s models revealed cities significantly affect plants’ springtime growth. “Not only are there other things going on, but they actually matter quite a lot,” said study co-author Brian Stucky, Florida Museum research scientist. Plants may not be the only organisms affected by seasonal shifts, he added. “Seasons are such a big part of our lives. We define our world around seasonal things. Those rhythms are what we think of as the normal way the world works.” 
8. Which of the following can be inferred from the passage?

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Elephants need a large amount of habitat because they eat so much. Humans have become their direct competitors for living space. Human populations in Africa and Asia have quadrupled since the turn of the century, the fastest growth rate on the planet. Forest and savanna habitat has been converted to cropland, pastureland for livestock, and timber for housing and fuel. Humans do not regard elephants as good neighbors. When humans and elephants live close together, elephants raid crops, and rogue elephants rampage through villages. Local people shoot elephants because they fear them and regard them as pests. Some countries have established culling programs: park officials or hunters kill a predetermined number of elephants to keep herds manageable and minimize human-elephant conflicts. Hunting has been a major cause of the decline in elephant populations. Elephants became prized trophies for big-game hunters after Europeans arrived in Africa. More recently, and more devastatingly, hunters have slaughtered elephants for their ivory tusks. The ivory trade became a serious threat to elephants in the 1970s. A sudden oil shortage caused the world economy to collapse, and ivory became more valuable than gold. In fact, ivory has been called “white gold” because it is beautiful, easily carved, durable, and pleasing to the touch. Most of the world’s ivory is carved in Japan, Hong Kong, and other Asian countries, where skilled carvers depend on a supply of ivory for their livelihoods  Hunting elephants is no longer legal in many African countries, but poaching was widespread until very recently. For many the high price of ivory, about $100 a pound in the 1980s, was too tempting to resist. Local people often had few other ways to make a living, and subsistence farmers or herders could make more by selling the tusks of one elephant than they could make in a dozen years of farming or herding. As the price of ivory soared, poachers became more organized, using automatic weapons, motorized vehicles, and airplanes to chase and kill thousands of elephants. To governments and revolutionaries mired in civil wars and strapped for cash, poaching ivory became a way to pay for more firearms and supplies. Poaching has caused the collapse of elephants’ social structure as well as decimating their numbers. Poachers target the biggest elephants because their tusks are larger. They often kill all the adults in the group, leaving young elephants without any adults to teach them migration routes, dry-season water sources, and other learned behavior. Many of Africa’s remaining elephant groups are leaderless subadults and juveniles.
5. Which of the following is NOT mentioned as a reason why ivory is valuable?

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The world is losing languages at an alarming rate. Michael Krauss suggested that of the approximately 6,000 human languages alive today, only 350 to 500 are safe from extinction. Some linguists estimate that a language dies every two weeks or so. At the current rate, by 2100, about 2,500 native languages could disappear. Languages become extinct for many reasons. Through imperialism, colonizers impose their languages on colonies. Some politicians believe multilingualism will fragment national interests. Thus they prohibit education in all but the national language. Another reason for language death is the spread of more powerful languages. In the world today, several languages, including English, are so dominant in commerce, science, and education, that languages with fewer speakers have trouble competing. Although in the past, governments have been one of the primary causes of language death, many have now become champions of preserving endangered languages and have had some significant successes. Two outstanding examples are the revival of Hebrew and Irish. Hebrew was considered a dead language, like Latin, but is now the national language of Israel. Irish was not dead, but severely threatened by English when the government of Ireland began its rescue immediately after the establishment of the Irish Free State in 1922. All students in public schools must now take some classes in Irish and there are Irish programs in major media, such as television and radio. According to the Irish government, approximately 37% of the population of Ireland now speaks Irish. One of the largest programs to revive languages, Documenting Endangered Languages (DEL), is being conducted by three U.S. government agencies: the National Science Foundation, the National Endowment for the Humanities, and the National Museum of Natural History. Researchers funded by these agencies are recording interviews with the mostly elderly people who still speak the languages. Analyses of these interviews will help linguists publish dictionaries and grammars of the languages. Eventually, linguists hope to establish language-training programs where younger people can learn the languages, carrying them on into the future. The linguists participating in DEL defend spending millions of dollars to preserve dying languages. They point out that when a language dies, humanity loses all of the knowledge of the world that that culture held. Traditional healers in rural areas have given scientists important leads in finding new medicines; aspirin is an example of these. But one of the most common reasons given by these researchers is that studying languages gives us insight into the radically different way humans organize their world. David Lightfoot, an official at the National Science foundation, gives the example of Guguyimadjir, and Australian aboriginal language, in which there are no words for “right” or left,” only for “north,” “south,” “east,” and “west.” Many researchers are optimistic that the efforts to save dying languages will succeed, at least in part. Bruce L. Cole, Chairman of the National Endowment for the Humanities, said, “Not only is this a time of great potential loss, it is also a moment for enormous potential gain. In this modern age of computers and our growing technological capabilities, we can preserve, assemble, analyze, and understand unprecedented riches of linguistic and cultural information.”
4. The word “revive” in paragraph 4 mostly means _______

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Insects’ lives are very short and they have many enemies but they must survive long enough to breed and perpetuate their kind. The less insect-like they look, the better their chance of survival. To look “inedible” by imitating plants is a way frequently used by insects to survive. Mammals rarely imitate plants, but many fish and invertebrates do. The stick caterpillar is well named. It is hardly distinguishable from a brown or green twig. This caterpillar is quite common and can be found almost anywhere in North America. It is also called “measuring worm” or “inchworm”. It walks by arching its body, then stretching out and grasping the branch with its front feet then looping its body again to bring the hind fed forward. When danger threatens, the stick caterpillar stretches its body away from the branch at an angle and remains rigid and still, like a twig, until the danger has passed. Walking sticks, or stick insects, do not have to assume a rigid, twig-like pose to find protection: they look like inedible twigs in any position. There are many kinds of walking sticks, ranging in size from the few inches of the North American variety to some tropical species that may be over a foot long. When at rest their front legs are stretched out, heightening their camouflage. Some of the tropical species are adorned with spines or ridges, imitating the thorny bushes or trees in which they live. Leaves also seem to be a favorite object for insects to imitate. Many butterflies can suddenly disappear from view by folding their wings and sitting quietly among the plants that they resemble 
1. What is the main subject of the passage?

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When living and working in another country, there are numerous things to consider  apart from the more obvious ones of climate, language, religion, currency, etc. Some important considerations are less obvious. For example, do you have a pet or do you enjoy a hobby such as horse riding? Your animal or hobby may be perceived in a completely different light in another culture so it’s important to consider the significance given to specific animals in different parts of the world and general perceptions towards them.  One example which is often mentioned in popular press is the case of dogs. In some cultures, like the US or UK, dogs are loved and considered a great pet to have at home and with the family. In other cultures, such as those where Islam is the majority religion, dogs may be perceived as dirty or dangerous. Muslims’ treatment of dogs is still a matter of debate amongst Islamic scholars . While these animals are widely considered by many Western cultures to be ‘man’s best friend’, the Koran describes them as unhygienic. Muslims will therefore avoid touching a dog unless he can wash his hands immediately afterwards, and they will almost never keep a dog in their home.  In Iran, for instance, a cleric once denounced ‘the moral depravity’ of dog owners and even demanded their arrest. If you are an international assignee living and working in Saudi Arabia or another Arabic country, you should remember this when inviting Arab counterparts to your house in case you have a dog as a pet. This is just one example of how Islam and other cultural beliefs can impact on aspects of everyday life that someone else may not even question. A Middle Eastern man might be very surprised when going to Japan, for instance, and seeing dogs being dressed and pampered like humans and carried around in baby prams!  Dogs are not the only animals which are perceived quite differently from one culture to another. In India, for example, cows are sacred and are treated with the utmost respect. Conversely in Argentina, beef is a symbol of national pride because of its tradition and the high quality of its cuts. An Indian working in Argentina who has not done his research or participated in a cross cultural training programme such as Doing Business in Argentina may be surprised at his first welcome dinner with his Argentinean counterparts where a main dish of beef would be served.  It is therefore crucial to be aware of the specific values assigned to objects or animals in different cultures to avoid faux-pas or cultural misunderstandings, particularly when living and working in another culture. Learning how people value animals and other symbols around the world is one of the numerous cultural examples discussed in Communicaid’s intercultural training courses. Understanding how your international colleagues may perceive certain animals can help you ensure you aren’t insensitive and it may even provide you with a good topic for conversation. 
5. The word “pampered” in the third paragraph could be best replaced by ______

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks.
Reference books are not designed to be read from the first page to the last but rather to be consulted to answer the questions and provide both general and specific pieces of information. One of the most (1)........-used reference books is a dictionary, which provides information about words. It lists meanings and spellings, tells how a word is pronounced, gives (2).............of how it is used, may reveal its origins and also lists synonyms and antonyms. To help you find the words faster, there are guide words at the top of each page showing the first and last words on that page - and of course it (3).......... to know the alphabet!
There may be numerous special sections at the back with facts about famous people and places, lists of dates and scientific names, etc. There is usually a section at the front (4)................. how to use the      dictionary, which includes the special abbreviations or signs.
An atlas is also a reference book and it contains charts, tables and geographical facts, as well as maps. Political maps locate countries and cities, physical maps show the formation of the land with its mountains and valleys, and economic maps show industries and agriculture. To find a specific place, you need to look in the (5).........      at the back of the atlas and the exact position on the map. There are      numerous map symbols that you need to know in order to be able to read a map-almost like a special language-and these are explained at the front of the atlas.

(3).......................

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Modern technology, in all its various forms, has changed the way we live our lives,  but unfortunately, (1) _______ has not always been for the better. A number of things we used to value highly are gradually disappearing or have disappeared altogether. Take punctuality, for example; before mobile phones, people had to keep their appointments and get to meetings (2) _______ time. Now, it seems, it is perfectly acceptable to send a text five minutes before you are due to meet, telling your friend or colleague not to expect you for another half an hour or so.  The Internet, too, has had a negative effect on our (3) _________. Rudeness seems to be the language of debate on any site which (4) ________ users to give their opinions. Anonymity makes it easier for people to insult anyone that has views which are different from their own. They lose all sense of politeness and restraint, safe in the knowledge that they (5) _______ never be identified

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There are a ………………… smokers in my family.

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Herman Melville, an American author best known today for his novel Moby Dick, was actually more popular during his lifetime for some of his other works. He traveled extensively and used the knowledge gained during his travels as the basis for his early novels. In 1837, at the age of eighteen, Melville signed as a cabin boy on a merchant ship that was to sail from his Massachusetts home to Liverpool, England. His experiences on this trip served as a basis for the novel Redburn (1849). In 1841, Melville set out on a whaling ship headed for the South Seas. After jumping ship in Tahiti, he wandered around the islands of Tahiti and Moorea.This South Sea island sojourn was a backdrop to the novel Omoo (1847). After three years awayfrom home, Melville joined up with a U.S. naval frigate that was returning to the eastern United States around Cape Horn. The novel White Jacket (1850) describes this lengthy voyage as a navy seaman. With the publication of these early adventure novels, Melville developed a strong and loyal following among readers eager for his tales of exotic places and situations. However, in 1851, with the publication of Moby Dick, Melville's popularity started to diminish. Moby Dick, on one level the saga of the hunt for the great white whale, was also a heavily symbolic allegory of the heroic struggle of humanity against the universe. The public was not ready for Melville's literary metamorphosis from romantic adventure to philosophical symbolism. It is ironic that the novel that served to diminish Melville's popularity during his lifetime is the one for which he is best known today.
2. According to the passage, Melville's early novels were:.......

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She has won a running competition . ---- _______________!

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During droughts water is scarce but is it possible to make it rain to provide water. Experiments in cloud seeding suggest that it may be possible to artificially create rainfall. Rainfall occurs when supercooled droplets of water – those that are still liquid but are at a temperature below the usual freezing point of zero centigrade – form ice crystals. Now too heavy to remain suspended in the air, these then fall, often melting on their way down to form rain. Even in dry areas the air usually contains some water. This can be made to come together and form ice crystals by seeding the atmosphere with chemicals such as silver iodide or dry ice. They work to promote rainfall by inducing nucleation – what little water is in the air condenses around the newly introduced particles and crystallises to form ice. The ‘seeds’ can be delivered by plane or simply by spraying from the ground. But does it work? It’s hard to tell for sure. As is often the case with weather and climate, it’s impossible to carry out a controlled experiment – so, in areas of increased precipitation, we can’t know whether it would still have rained even if the clouds hadn’t been seeded. Success has been claimed for trials in Australia, France, Spain and the US. In the United Arab Emirates, the technique is credited with the creation of 52 storms in the Abu Dhabi desert, while China boasts of having used the technology in reverse to keep the Beijing Olympic Games of 2008 dry. Recent research, however, suggests that it’s not as effective as was previously believed  
5. The word “credited” in paragraph 5 is closest in meaning to ______

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Most sources of illumination generate light over an appreciable period, and indeed if  an object is lit for a very brief time(less that 1/25 second), the human eye will not react in time to see the object. A photographic emulsion - that is, a light-sensitive coating on photographic film, paper, or glass - will, however, record much shorter bursts of light. A photographic flash can therefore be used to capture high-speed movement on film as well as to correct deficiencies of the normal surrounding lighting. Photoflash is now generated electronically, but the earliest form, first used in 1864, was a paper bag containing magnesium wire and some oxygen-rich substance, such as potassium chlorate. When the bag was ignited, the metal burned with an intense flash. A contemporary observer reported that “this quite unsafe device seems to have done nothing worse that engulf the room in dense smoke and lead to pictures of dubious quality and odd poses.”  The evolution of the photoflash was slow, flashbulbs, containing fine wire made of a metal, such as magnesium or aluminum, capable of being ignited in an atmosphere of pure oxygen at low pressure, were introduced only in the 1920’s. In the earliest type, the metal was separated from the oxygen by a thin glass bulb. The flash was fired by piercing the bulb and allowing the oxygen to come into contact with the metal, which ignited spontaneously. Later bulbs were fired by an electric battery, which heated the wire by passing a small current through it. Other combinations, such as the pairing of oxygen difluoride with zirconium, have also been used. In each case enough energy is given out to heat the oxidizable metal momentarily to a white hot emission of visible light. The smoke particles are so small that they cool rapidly; but since they are white, they contribute to the brilliance by reflecting the light from their still glowing neighbors. A slightly bigger form of the metal will burn for a longer time. 
1. What is the best title for the passage?