Question

【题目】Sam, ________ your teeth before going to bed.

A.is brushingB.brushesC.brushD.has brushed

Answer 1

【答案】C

【解析】

句意：Sam，睡觉前刷牙。

考查祈使句。is brushing现在进行时；brushes第三人称单数；brush刷，动词原形；has brushed现在完成时。根据Sam, ___ your teeth before going to bed.可知本句为祈使句，所以此处应用动词原形，故答案选C。