at the door before you enter my room, please.A. Knock B. Knocking C. Knocked D. To knock

发布时间：2020-08-16 23:22:42

     at the door before you enter my room, please.
A. Knock
B. Knocking
C. Knocked
D. To knock

网友回答

(答案→)A. Knock
B. Knocking
C. Knocked
D. To knock
解析：考查祈使句。祈使句都是把动词原形放在句首的。故A正确。句意：进来之前请敲门。故A正确。
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