题目内容：

根据短文内容，将下面A—E五个句子分别填入文中空缺处，使补全后的短文意思通顺，结构完整。

There are many different kinds of animals in the zoo. We see the zoo keepers give them food to eat.    1.   . They just eat, walk and sleep all day.   2.  . But in fact most of them are sad. Why?   3.   .

Animals like monkeys and tigers usually live freely and happily in forests or mountains. Tigers, for example, run, jump, play with their children.      4.  . But now they have to stay in the small rooms in the zoo. Their life there is different from that in the forests.

5.  . Do you think so?