l was late for Mr. Smith’s oral classthis morning.—_____ As far as I know, he never came late toclass.

If you have a toothache（牙疼）, you should see a .

The Three Gorges Dam can produce _________ for millions of people every year.

He did well in the examination. He _____hard at his lessons..

The search was________when night came,even though the child had not been found. [ ]