题目内容：

The crow （乌鸦）is an ordinary（普通的） bird. It is about twenty inches（英寸） long and black all over. Crows are dirty birds because they live on old bad food. Crows eat a lot of waste food. In this way they are more useful to us than any birds. They clean up the dirty things in our streets. Crows are always hungry. They look for food all day long, and in the evening you can see them in large numbers flying back to their nests（窝） in the trees. They sleep there at night.

Crows are much noisier than other birds. Very often a large number of crows will get together on one house and talk. Sometimes they talk together, and sometimes they do it by turns like human beings（人类）. It is easy to tell from（区别） crows’ sounds whether they are pleased or angry. Perhaps crows talk a lot because they are friendly birds. A pair of crows will live together all their lives, and if one of them dies, the other one becomes very sad and quiet for the rest of its life and sometimes it dies, too.

1.Why are crows dirty?

A. They are black all over the body.

B. They like to eat dirty food.  

C. They usually talk.

D. They don’t have baths. 

2.Why are crows more useful to us than any birds?   

A. They are usually noisy.

B. They are usually dirty.

C. They are flying in large numbers.

D. They eat a lot of waste food.

3.You can tell from crows’ sounds _________.   

A. whether they are hungry or full

B. whether they are pleased or hungry

C. whether they are ill or healthy 

D. whether they are living or dead.