We are used to the idea of aging in ourselves. We are so used to this that it comes as a surprise to find that there may be some animals that do not age. Sea anemones(海葵) are an example. Some have been kept for nearly a century without showing any signs of lifelessness. Some kinds of sea worms can even “grow backwards.” If kept in the dark and given nothing to eat, they get steadily smaller, They finally end as a ball of cells(细胞) looking rather like the egg from which they came. Under good conditions the ball will turn back to a worm and start growing again. One could probably keep them growing and un-growing again and again.

　　1. Some sea worms grow smaller when they ______.

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　　A. lose weight B. live in the darkness

　　C. are under good conditions D. don’t eat and are kept in the dark

　　2. According to the passage, some sea animals ________.

　　A. will die when they become a ball of cells B. do not grow old

　　C. will die without food D. will stop growing any time they want

　　3. According to the passage, which of the following statements in NOT true?

　　A. We can keep certain kind of sea worm growing and ungrowing again and again.

　　B. Human beings will grow old and die.

　　C. An anemone is a king of sea worm that can grow backwards.

　　D. Some anemones will live nearly a hundred years.

　　4. The underlined word aging in the first sentence means ______.

　　A. growing old B. the age of a person

　　C.getting younger D. un -growing

　　5. This passage is mainly about ______.

　　A. sea animals B. cells C. aging D. anemones

　　参考答案:

　　1D 2 B 3 D 4 A 5 C

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