Just at that time,I heard someone____at the doorA.knockB.knocksC.knockedD.to knock

问题描述:

Just at that time,I heard someone____at the door
A.knock
B.knocks
C.knocked
D.to knock

就在那一时刻,听到了某人做某事,做的动作用原形A

就在那时,我听到有人在敲门
敲门为knock at the door
hear的用法为hear sb.do/doing sth.
选A