用所给词的适当形式填空，每空不限一词。

1. I think it's _________(use) to talk with him. It's difficult to change his mind.

2. The terrible snowstorm kept them from _________(ski) last week.

3. My uncle will come back from London. I'm waiting for his _________(arrive).

4. _________(wolf ) eat smaller animals when they are hungry.

5. _________(luck), he was hurt badly.

6. His grandpa was lucky enough to stay _________(live) during the earthquake.

7. Lushan is so beautiful that he wants to go there for the _________ (two) time.

8. We should encourage people _________ (not cut) trees any more.

9. I _________ (drive) to Beijing when my car broke down.

10. The young trees _________ (die) soon if you don't water them in time.