My deskmate is still a puzzle to me; at one moment he is quiet while at another he _____ be quite active.
If you are worried about the problem,you should do something it.
We’ve talked a lot _______ cars. What about trains?
We’re all going to the games.Why don’t you come ?
It was very kind of her. She insisted _______ her car to us.
We offered him our congratulations his passing the college entrance exams.