When lost in work , ______ he often was , he would forget all about eating and sleeping.
-- How was your life in the countryside? -- It was _______ but sometimes I felt a bit _______.
Stop making noise, _______ the neighbors will start complaining.
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.