—As a teenager,our son should have two or three hobbies to be really happy.—________,but how can he afford the time with so much homework every day?
The traditional view is ____ we sleep because our brain is “programmed” to make us do so.
Then you usually lie there just ______ the ceiling, thinking about everything that could go wrong.
—What do you think of his opinion? —None has given me ___________ piece of advice.
The boy should be punished. You shouldn’t let him ______ cheating in the exam.
You can only be sure of _____ you have at present;you cannot be sure of something _____ you might get in the future.