1. (2021八上·慈溪竞赛) 根据短文内容，用方框中所给单词的适当形式填空，每词限用一次。

as long as       pollute     possible    during      little

1. （1） The water is serious in this city.
3. （2） He is the best teacher though he has the experience. (经验)
5. （3） You can go out, you can come back before 10:00 p.m.
7. （4） I saw Tina once my stay in London last year.
9. （5） The question is too difficult. It is for him to answer it.