How time flies! Three years _________ since I _________ you last time.

______ we ______ to these immediate crises abroad, we also will not let up in our effort to deal with the pressing, ongoing challenges facing our country

You’d better take something to read when you go to see the doctor ________ you have to wait.[ ]

ou got the final result—Yes, very disappointing. We________ have won thegame.

If there are _____people driving, there will be ______air pollution.—Yes, the air will be fresher and cleaner.