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 “depletion” in paragraph 2 probably mean?

Câu hỏi liên quan

• What is the main topic of the passage?

• Which of the followings is not mentioned as part of the “new media”?

• According to the passage, the Eric Canal connected the .............

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• The word “doubtless” in the passage mostly means ...............

• The word "remainder" in paragraph 2 is closest in meaning to .............

• Which of the following statements is supported by the passage?

• Which of the following sentences is true?

• What killed an estimated 500,000 people in Bangladesh?

• Which is the most popular sport in the US?

•  The text is mainly about __________.

• Which of the following is true of standard usage?

• As used in paragraph 2, the word "seeking" could best be replaced by which of the following?

• The orchid is unique because of ......

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

• The word “retrieves” in paragraph 4 is closest in meaning to _______.

• In the first paragraph, the word "emerged" is closest in meaning to ...........

• What is the passage mainly about?

• According to the passage, what must the nations of the world do to find a solution?

• The passage mainly discusses costume in terms of its _______

• The word “they" in paragraph 5 refers to ................