Iraq has ___________ too many wars since 1990s, making his people ______ a lot.
This school has strict rules. Almost no one can ________ cheating in exams.
Though we have been staying up for days, there’s still _____ work remaining to be done.
It is strange that the small boy _________ work out such a difficult exercise, which is even hard to settle for adults.
His wife has left him, but he behaved _______ nothing had happened.
Clearly, in a system _________ every decision is made on the basis of tradition alone, it may be difficult to achieve progress.