用单词的适当形式填空。    

1. It was difficult  ________(build) the railroad for us.

2. What's ________ (he) name ?

3. Are those ________ (girl) your ________ (classmate) ?

4. He ________ (wave) to me and smiled .

5. The British ________ (bridge) are very nice .

6. We ________ (not,have) chicken but fish for lunch yesterday.

7.  —How long ________ it ________ (take) you to finish your homework last night?

     —Tow hours.

8. Yang Liwei is the ________ (one) astronaut of China.

9. These ________ (hero) are from Africa.

10. They ________ (build) the railroad five years ago.