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This is a very important question.Many Chinese students often  study  very hard for long hours.This is a  good  habit.But it is not the best way to study.An efficient student must  have  enough sleep, enough food and enough rest.Every week you  should  go out for a walk or visit some friends or some nice places.This is good  [MASK]  you.When you return to your studies, you'll find yourself  stronger  than before and you'll learn more.