I don’t know why you are so concerned — it’s not your problem _____ .
The best job is_______which uses your skill in doing something together with your interest in the subject.
——There must be a dozen pens in this house but I can never find one when I need one. ——Keep looking. ______is sure to turn up.
Who can you turn to in time of danger, it not ________.
——Which of the two books do you want? —— I want_______. Please show me________.
Some people would rather ride bikes as bike ridding has_________ of the trouble of taking buses.