请看下面的句子：Who is knocking at the door?I think (it) is Li Lei.为什么要用it?

请看下面的句子：Who is knocking at the door?I think (it) is Li Lei.为什么要用it? 定语从句的省略情况,请看下面两个句子This is my brother ( who is) going to Australia.The man ( who is ) standing behing the counter.为什么第一句中who is 不能省略,第二句中who is 可以省略 Who is _____ ( knock It is me. 请看下面句子 1.Mike is the person whom you talked about on the bus.为什么这里要用whom 不用who? 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? 现在分词和过去分词作状语请看清楚我的问题：1.现在分词作状语 与 过去分词作状语 的区别2.过去分词作状语时是不是要省略Be动词3.请看下面句子：The worker who has worked there is moving to Shenzhen this flowerpot is broken .who knocked it___ knock over knock off 有什么区别 , 亲们,请看下面的题目： 中译英：请看下面的截图 英语翻译请看下面的内容！ When you hear a knock on the door,what will you say?用who is it?回答时为何要用it,门外站的是人啊用who are you? 1.请看下面的表格,然后用表示频率的副词写句子. i think someone is in .let's knock the door 这句话的knock为什么要改成knock at knock over knock off?有一题:this flowerpot is broken,who knocked it_______?应该填over还是off?为什么?这是新概念2,第6课的填空题.倒底填什么?希望有更多回复 为什么是is knocking：Who is knocking(knock) at the door?it's me. knock knock lenka 的链接 将下面的句子填写完整Who's this ___ Is he your father?No,he;s my uncle. 关于knock的短语!This flowerpoot is broken,Who knocked it ____I knocked ______ early yesterday and went to a football match.