21.  May.

22.  When you come into the gate of the People's Park, you May go down the rode which is near a small river.

23.  I think you May have a question: why the river turned dirty.

24.  We didn't go home after school so that we May have more time to pratise .

25.  May our head teacher represent the public?

26.  A good cooker May be do bad in his first .

27.  In my opinion, you must practice more so that you May be skillful and perfect in what you are doing.

28.  On the other hand, they May not know many courses as we do.

29.  For example, when we begin with learning English we May feel it is difficult to learn.

30.  For example, at the beginning of studying English, we May feel much trouble to us.