所给词的适当形式填空。

1. My mother can't sleep well, and sometimes she even stays _____ (wake) the whole night.

2. Be careful to cross the street when we meet heavy _____ (traffic).

3. _____ (polite), he drove the old man out of the room and shouted at him angrily.

4. They expected that they could solve the problem by _____ (they).

5. _____ (thousand) of students rushed out to celebrate their victory (胜利).