1. 用方框中所给短语的适当形式填空。

be harmful to, ask for, change...into, turn off, look after

1. （1） Remember to the light when you leave the room.
3. （2） Fast food your health. You shouldn't eat it often.
5. （3） We our teacher the best way to learn English.
7. （4） It's impossible to the iron gold.
9. （5） My job is animals in the zoo.