Suddenly he heard someone（）gently on the window.
A: knock
B: knocking
C: knocked
D: to knock
A: knock
B: knocking
C: knocked
D: to knock
举一反三
- I heard someone _______ loudly at the door while I was listening to the radio. A: knock B: knocking C: to knock D: knocked
- I was almost asleep last night when I suddenly heard someone _____ at thedoor.(2013年真题） A: be knocking B: knocking C: to knock D: having knocked
- knock at/on 敲knock into 撞到某人身上knock down 撞倒knock out of 把…敲出knock over 撞倒knock off 停止工作，休息1) The boxer soon knocked his opponent ________ __.2) The office stuff knocks _________ ___ at six every day.3) Try knocking __________ ___ the window and see if there is anyone indoors.4) He was so absorbed in his book that he knocked __________ _____ the car parked there.
- He had three of his teeth _______ out in the fight. A: knocking B: knock C: knocked D: be knocking
- A: Listen! There__________ someone __________ at the door.B: It must be your sister. A: is; knocking B: is; knock C: are; knocking D: are; knock