knock at the door before entering please句中只有KNOCK AT 一个动词?en

knock at the door before entering please句中只有KNOCK AT 一个动词?en knock at the door before entering please这句话是时间状语从句吗? 英语改错 “Please knock the door before entering.” please knock at the door before you enter the room（同义句转换） Please knock at the door before you enter the room .(同义句转化)) 同义句转换Please knock at the door before you go into the room knock at the door ____ at the door before entering,please knock at the door造句 关于knock at the door. ______ at the door before you enter my room, please. A．Knock Please ____(knock)at the door when you come in.