He studies the subject _____.
---- What do you know about the population of China? ---- It _____ over 1,200 million and 80 percent of it _____ peasants.
It will take _____ time to finish the project.
It is not rare in ____ that people in ____fifties are going to university for further education.
Has ____ how many spies we caught during the war ____ up to now?
You’ve missed your ______ to speak and you have to wait for another round.