21.  Children have to do a lot of housework so that their parents can go to fields and grow crops.

22.  They must do a lot of labour for the Emperor.

23.  An excellent worker can do a lot of things in a very short time.

24.  In English, If you want to pass the ETC-4 , You should do a lot of English excerises .

25.  It means that we must do a lot of practice if we want to do better.

26.  During the first period of playing piano, we have to do lots of easy and boring exercises.

27.  Once you have learned how to deal with this kind of problems, you must do a lot of problems of this kind to add your practice.

28.  So, we should do a lot to deal with it, but how?

29.  In order to improve the studets ' score, their teachers let them do a lot of homework.

30.  We can't study, work and do a lot of interesting things without good health.