用所给单词的适当形式填空

1. More and more young people are trying to do something  _________( serve) the old.

2. The doctor did what he could_________ (save) the  dying man.

3. The teacher asked Ben___________(answer)a difficult question in class.

4. Don't forget___________ (see) my parents when you are in  Shanghai.

短命植物与类短命植物一般分布在苔原。 [ ]