I. 用所给词的适当形式填空 1. You should________ to school early.(come) 2. You had better ____ ( lie ) down and _____ ( have ) a rest, because you are too _____ ( tire ). 3. You must keep your eyes __________ (close) for ten minutes. 4. My job is_________ the blackboard.(clean) 5. I have a ____ ( tooth ). The doctor says I must have the medicine three _____ ( time ) a day.