at the door before you enter the office，or you’ll be considered impoliteA. KnockingB. Knoc

发布时间：2020-08-17 10:21:14

    at the door before you enter the office，or you’ll be considered impolite
A. Knocking
B. Knocked
C. Knock
D. To knock

网友回答

A. Knocking
B. Knocked
(答案→)C. Knock
D. To knock
解析：考查祈使句。本题考查祈使句 + and / or + 陈述句结构，故用动词原形。句意：在进办公室之前敲门，否则你会被认为不礼貌。故C正确。
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