发布时间：2016-08-11 来源：新东方在线 发布人：继续
When we can see well, we do not think about oureyes very often. It is only when we cannot seeperfectly that we come to see how important oureyes are.
People who are nearsighted can only see thingsthat are very close to their eyes. Many people who doa lot of close work, such as writing, reading andsewing, become nearsighted. Then they have to wear glasses in order to see distant thingsclearly.
People who are farsighted(近视的) suffer from just the opposite problem. They can seethings that are far away, but they have difficulty reading a book unless they hold it at arm‘slength. If 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. 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 thecataracts and remove them.
When night falls, colours become fainter to the eye and finally disappear. After your eyeshave grown used to the dark, you can see better if you use the sides of your eyes rather thanthe centers. Sometimes, after dark, you see a small thing to one side of you, which seems todisappear if you turn you head in its direction. This is because when you turn your head, youare looking at the thing too directly. Men on guard duty sometimes think they see somethingmoving to one side of them. When they turn to look straight at it, they cannot see it any more,and they believe they were mistaken. However, this mistake happens because the center of theeye, which is very sensitive(敏感的) in daylight, is not as sensitive as the sides of the eyesafter dark.
1. We don‘t know that our eyes are of great importance until _____.
A.we think about our eyes
B.we cannot see clearly
C.we wear glasses
D.we have to do much reading
2.According to the passage, a _____ is more likely to be nearsighted.
A. tailor B. doctor C. guard D. painter
3. Those who suffer from cataracts _____.
A.will become blind
B.cannot be cured (治愈)
C.may be cured
D.must move to other places
4. People who are farsighted _____.
A.cannot do a lot of close work without glasses
B.can only see things that are very close to their eyes
C.have difficulty reading a book if they hold it at arm‘s length
D.have the same problem as the nearsighted people
5. to see a small thing at night, it is better to look ______.
A.with wide open eyes
B.with half- shut or narrowed eyes
C.straight at it
D.in a slightly different direction