Tom took the police to the spot ____ the accident happened.
Our plan to ______ a New Year’s party has won supports from our teachers.
—Bob has gone to California.—Oh, can you tell me when he ______?
Leave your key with a neighbor _____you lock yourself out one day.
It was two weeks before the Spring Festival and the shopping centre was _____ with shoppers.
Many students go to school _______ the tube in Beijing every day.