单选题 Our teacher often tells us ______ quietly in the library.

单选题 The boss made the workers ______ for 12 hours a day in the past.

单选题 My mother wants me ______ too much junk food. It’s bad for health.

单选题 I saw him ______ basketball on the playground just now.

单选题 Listen! I can hear someone ______ in the next room.

单选题 You must stop ______ so much noise. The baby is sleeping.

单选题 Though it was late, they kept ______ on the problem.

单选题 I forgot ______ the door when I left home this morning.