22. do house work做家务事

21. do homework做家庭作业

20. activity survey活动调查

19. as for至于

18. shop=go shopping

=do some shopping 购物

17. most of the students=most students

大多数学生

16. although=though虽然

15. how often 多久一次

14. make a difference to 对什么有影响

13. twice a week一周两次