1. 用方框中所给单词的适当形式填空。每词限用一次。

medicine, danger, sky, improve, build

1. （1） I'll not swim in the river near my home because I think it's.
3. （2） Look at this new building! It took workers about two years to it.
5. （3） I'm going to take writing lessons next term because I'd like to my writing.
7. （4） Please take this three times a day and you'll get better soon.
9. （5） The is getting dark. It's going to rain soon.