翻译并完成句子：

1. I’m ______________________(盼望着)hearing from you soon.

2. What’s your _________________(对……态度) this problem?

3. The students in our class__________________(分成) six study groups.

4. We should listen to our teachers carefully in class and ________________(避免出错) when doing our homework.

5. The other day, they boy student _________________(承认玩了电子游戏) deep into the night the day before.

6. The man  ______________________(刚才提到的) has left .

7. I _______________ work in the countryside______________ work in the city.(宁愿……而不)

8. I’m sorry. But your ticket ___________________(过期了)

9. Ads ____________________(缩写) advertisement.

10. We are not children now. We ________________(不应该再玩了。)

空气滤清器的功用是什么？