knock at the door before entering please句中只有KNOCK AT 一个动词?enter为什么不是?

knock at the door造句 Listen:Someone ______(knock) at the door. knock at the door敲门应该是knock at the door,有时也看到有用knock on the door的,还有是不是可以直接说“knock the door呢? 关于knock at the door.为什么不是knock the door? at表示什么? knock at the door 和 knock on the door有什么区别吗详解,谢 knock at the door和knock on the door到底有什么区别? they were i______ by a knock at the door Listen!There's someone_____(knock)at the door. Listen!There's someone_____(knock)at the door. Please ____(knock)at the door when you come in. Listen,someone______(knock)at door i think someone is in .let's knock the door 这句话的knock为什么要改成knock at There was a knock at the door.(改为同义句)_____ ______ ______ the door. Listen!I hear someone knocking at the door.Listen!_____ ______ a knock on the door. knock at the door before entering please句中只有KNOCK AT 一个动词?enter为什么不是? please knock at the door before you enter the room（同义句转换）please knock at the door _________ __________the rooom 敲门英语可以说成 knock at on the door 因为书上写 knock at (on) the door on 是可以省略么? 27 If nobody answers the door bell ,try ___ the back door.A to knock at b.to knock c.knocking at d.knocking 需要详细分析