根据句意及汉语提示完成句子。
1. We should not_____ (坏，破坏) our environment.
2. The school is making_____(努力) to help poor students.
3. Smoking can_____(引起) lung cancer.
4. The policeman_____(命令) the thief to raise his hands.
5. It's wrong to_____(污染) the village.
6. You must____(签名) in when you come to the center.
7. My mother doesn't____(允许) me to play computer games.