小白淼淼
knock at the door.To see the manager, knock at the door marked"private". 要见经理,请敲标有“私人的”字样的房间。When I heard the knock at the door, was the frightened out of my senses. 一听见有敲门声我就吓得六神无主。
浮云秋叶
答案:knock at. 首先通过中英文句子的比对,可知英文句子中缺少"敲门"的表达.短语"敲门"的英文表达是:knock at.本题中,句子是一个祈使句判断用动词原形,故答案为:knock at