可以说there is a knock at the door吗这里的介词是用at还是用on?knock at和knock on有什么区别呀?P.S.上课时老师讲的是用on,我不太确定,是真的这样吗?

可以说There is a pen here吗 可以说there is a knock at the door吗这里的介词是用at还是用on?knock at和knock on有什么区别呀?P.S.上课时老师讲的是用on,我不太确定,是真的这样吗? 解释下这句话Knock,knock jokesKnock,knock jokes是现在美国人长说的,原台词是knock,knock,knock,who is there? one night,they sit down for dinner and there is a knock at the door. knock over和knock down的分别?A car knock the boy over!可以说成是A car knock over the boy!knock over和knock down可以互相替换来用吗? 21页7.Listen ,there is a knock ------the door .It must be TomA.on B.to C.in 理由 —There is a knock at the door.—---------------?A.who is that?B.who can it be?...—There is a knock at the door.—---------------?A.who is that?B.who can it be?C.who is he?D.do you think who he is?a和c为什么不对啊 变为否定句 Jack can drive a car ,too Jack ( )drive a car ,( )变为同义句There is a knock at the door.Someone ( ）（ )at the door. Class Two ____ taking their lessons when there was a knock at the door.为什么A. is B. are C. was D. were my home英语短文可不可以说There is my bedroom? 就是说可以说There is many grass in the field. 1.S_____ there was a knock on the door.结合句意根据首字母填空 there was a knock on the door.急…………………… There was a knock at the door.(改为同义句)_____ ______ ______ the door. There came a knock on the door请问这句话的正常语序 there came a knock on the door这个句子有错吗? He was sleeping when there was a loud knock at the door.[对sleeping提问] ____ I was falling asleep,there was a loud knock on the door.(when/while)