— I can’t decide __________or not I should encourage my son to be a volunteer.— Why not? It will make him more helpful.
Mr. Wu is one of __________ in our school.
Nancy spent half an hour _______ playing the piano every day.
You must be tired now. Why not ________ to have a rest?
The little boy often makes his mother tell him ____________.
---Mum, can I do the homework tomorrow? ---You _____ finish it today.