B 根据 It is only when we can not see perfectly that we come to see how important our eyes are
A Many people who do a lot of close work,such as writing and reading,become nearsighted.
D They can see things that are far away,but they have difficulty reading a book unless they hold it at arm’s length.
D After your eyes have grown used to the dark,you can see better if you use the side of your eyes rather than the centers.
亲,答案都在文中,后边是与答案相关的句子,