题目内容：

根据句意从方框中选择合适的动词，并用其适当时态填空。

1.I was reading a book while my mother ___________.

2.Mary often __________ shopping on weekends when she was at primary school.

3.Didn’t your teacher tell you that sound ________ more slowly than light?

4.If everyone can take action to protect the environment, the world _______ more beautiful.

5.I won’t go to see the film tonight, because I __________ my ticket.