1. 根据语境从方框中选择恰当的短语填空，有的需要变换形式，每个短语限用一次。

Join in, be good for, clean up, look after, be made of, pay attention to

1. （1） Mary is too young to  herself.
3. （2） We must  the weather during the trip
5. （3） Jack likes swimming because it  his health.
7. （4） I hope that everyone will be able to  the talk.
9. （5） These cups look beautiful. They  china.
11. （6） Let's  the broken glass immediately before someone walks on it.