To be on the safe side, we should fill up the tank now, because we ______ run out of gas on the way.
If better use is ____ your spare time , you will make greater progress.
— Did you call on any of your old friends when you returned to your hometown ? —______ of them . They were all very busy .
It took seven years __________ they finally got married.
The students asked me ____________ going to be held.
In the past month, cruel snowstorms hit some European countries and America ,great transportation problems in these countries.