1 i can't understand what he said.
2 the work we are doing is very important
3 what he has said is helpful to us
4 he has a good account of the life in army
5 what you are trying is too hard for you
6 what you have told to us makes us to be amused
7 i don't know what measure he will take on this thing
8 what you have done is none of my business
9 tell me what you will do in the summer holiday