You should book a train ticket_____ if you want to go home in time before the Spring Festival.
Many students go to school _______ the tube in Beijing every day.
It was two weeks before the Spring Festival and the shopping centre was _____ with shoppers.
Leave your key with a neighbor _____you lock yourself out one day.
—Bob has gone to California. —Oh, can you tell me when he ______?
Our plan to ______ a New Year’s party has won supports from our teachers.