Today I’d like to begin a discussion on the problem of the heating up the earth. First, we’ll touch on the relationship between fluorocarbons and the ozone layer. You probably remember that the ozone layer is the protective shield around the earth. It is important to all life, because it filters out harmful ultraviolet light from the sun. Ozone itself, a form of oxygen, is regularly made by the action of the sun in the upper atmosphere. It is also regularly destroyed by natural chemical processes.

The problem now is that too much of the ozone layer is being destroyed. Scientists suspect that certain chemicals, such as fluorocarbons, are contributing to the depletion of the ozone layer. And how do we use fluorocarbons? The most common uses are in spray cans and cooling systems. The chemical pollution from these fluorocarbons can account for some of the ozone losses that have been reported. There are, however, new studies linking the sun itself to the depletion of the ozone layer. We’ll go into that new study more next time.

What does the word “filters out” in paragraph 1 probably mean?

Câu hỏi liên quan

• It can be inferred from the passage that the Puritans who traveled to the Massachusetts colony were __________.

• Which of the following concepts is defined in the passage?

• It can be inferred from paragraph 1 that___________

ZUNIA12

• Which of the following words is most similar to the meaning of “rustic”?

• The passage would most likely be required reading in which course?

• Approximately how much of the Earth’s atmosphere is nitrogen?

• Why did the author write the passage?

• Around what time did the university begin to appear?

• The four boys of the Beatles .................

• The word “derived” in paragraph 2 is closest in meaning to ______.

• The author mentions all of the following as jobs held by Moore EXCEPT ________

• A housewife’s services in a family of five people are worth ............

• The author states that "On the average, people can keep about seven ideas in their minds at once" (paragraph 3) to explain that .....

• What percent of the total rainfall on the earth does the Amazon rain forests receive?

• According to the passage, people respond to loud noises in the same way that they respond to ___.

• Look at the verb accelerate in paragraph 3. Which of the following is the closest in meaning to _____.

• Which word is similar in meaning to the word “glue”?

• "Negative publicity" in the passage most likely means .................

• With which of the following topics is the passage primarily concerned?

• The phrase broke out in paragraph 2 is closest in meaning ...............