阅读理解。根据下面短文内容，在短文的空格处填上一个恰当的词，使短文完整、通顺。

     Our eyes are very important to us. They are like cameras. We can see beautiful things and colors around

us.  1  our eyes. But if we don't take care of them, they may hurt.  2  do we protect our eyes?

     On sunny days, the sun shines brightly. So we'd better  3   our sunglasses. When we read, we shouldn't

stay too close to our books and the light shouldn't be too bright  4  too dark. We mustn't read in bed. It's  5   

for our eyes. We mustn't rub our eyes with dirty hands or play games on computer too long.