单选题 When we see well, we do not think about our eyes very often. (76) It is only when we cannot See perfectly that we realize how important our eyes are.
People who are near-sighted can only see things that are very close to their eyes. Everything else seems blurry (unclear). Many people who do a lot of work, such as writing, reading and sewing, become near-sighted.
People who are far-sighted suffer from just the opposite problem. They can see things that are far away, but they have difficulty in reading a book unless they hold it at arm's length, lf they want to do much reading, they must get glasses, too.
Other people do not see clearly because their eyes are not exactly the right shape. They have what is called astigmatism (散光). This, too, can be corrected by glasses. Some people's eyes become cloudy because of cataracts(白内障). Long ago these people often became blind. Now, however, it is possible to operate on the cataracts and remove them.
Having two good eyes is important for judging distances. Each eye sees things from a slightly different angle (角度). (77) To prove this to yourself, look at an object out of one eye; then look at the same object out of your other eye. You will find the object's relation to the background and other things around it has changed. The difference between these two different eye views helps us to judge how far away an object is. People who have only one eye cannot judge distance as people with two eyes can.

单选题 We should take good care of our eyes ______ .
A. only when we can see well B. only when we cannot see perfectly
C. even if we can see well D. only when we realize how important our eyes are

【正确答案】 C

【答案解析】主旨题。问题中提到我们应该爱护眼睛，而文章开头从反面提到当人们的眼睛很好的时候不会注意保护眼睛。后面几段紧接着说到眼睛问题，最后一段没总结重要性，所以纵览全文，应该得出结论C。A、B、D说法太绝对应该排除。

单选题 When things far away seem indistinct (模糊不清), one is probably ______ .
A. near-sighted B. far-sighted C. astigmatic D. suffering from cataracts

【正确答案】 A

【答案解析】细节题。第二段开始提到：“People who are near-sighted can only see things that are very clese to their eyes． Everything else seems blurry(=unclear)．”近视的人只能看清近处的事物，其他一片模糊。问题从反向提问，看不清远处事物的也就是近视眼。因此答案为A。

单选题 The underlined words "suffer from" in the third paragraph probably means ______ .
A. experience B. imagine C. feel pain D. are affected with

【正确答案】 D

【答案解析】词汇题。根据句意：“有远视的人会suffer from相反的问题。”experience意为“经验”；imagine意为“想像”； feel pain意为“感觉痛苦”；are affected with意为“受影响，受侵害”。选项D最贴切。

单选题 Having two eyes instead of one is particularly useful for ______ .
A. seeing at night B. seeing objects far away C. looking over a wide area D. judging distances

【正确答案】 D

【答案解析】细节题。第五段的第一句话和最后一句话给出了答案：“Having two good eyes is important for judging distances．”和“People who have only one eye can not judge distance as people with two eyes can．”由此可以得出用两只眼睛代替一只眼睛最关键的是帮助人们判断距离。

单选题 People who suffer from astigmatism have ______ .
A. one eye bigger than the other B. eyes that are not exactly the right shape
C. a difficulty that can be corrected by an operation D. an eye difficulty that cannot be corrected by glasses

【正确答案】 B

【答案解析】细节题。第四段的首句说明了“散光”的定义：“Other people do not see clearly because their eyes are not exactly the right shape．They have what is called astigmatism(散光)，”由此可知B为正确答案。