单项选择题

I heard somebody ______ at the door.

A．knocked
B．to knock
C．knock
D．knocking

<上一题目录下一题>

热门试题

单项选择题

A．twice the size of
B．as twice the size
C．as twice as
D．twice the size as

填空题

Guest: Thank you so much for the wonderful meal. Both my wife and I appreciate your invitation and warm treatment. Hostess: （）