Working hard is not a _______ of great success, but it is among the essential requirements.
Look out! Don’t get too close to the house________ roof is under repair.
Though he failed in the experiment again and again, he didn’t______, and at last, he made it.
Only in this way_______ finish the work ahead of time.
--Do you know the man _______ I shook hands just now? --Yes, I know him. He is a famous actor.
At present,_____ number of students are near-sighted and, what’s worse, _____number of them is increasing.