是he had sit down还是sat?为什么还有：是he wasn't worry 还是worried?为什么?我还认为wasn't应换成didn't,可是书上是这样写的.为什么?好的加50!一楼的只回答了2个！另外，worry不是动词吗？

I said''Tom,sit down.'' 怎么变成间接引语 是I told Tom to sit down 还是 He(she) told Tom to sit down the teacher didn't sit down until he saw every student already had a chair____A to sit B to sit down C to sit at D to sit on 原因是什么呢 其他选择为什么不能选 Sit down,please的回答是OK还是Thank you Hardly ___ down ___ he stepped in.A.had I sat, when B.had I sat, than C.I had sat, when D.did I sit, than请高手为我讲下其中的语法知识,这道题究竟该选哪个?是用一般过去时还是用过去完成时,我将感激不尽,谢谢! 是he had sit down还是sat?为什么还有：是he wasn't worry 还是worried?为什么?我还认为wasn't应换成didn't,可是书上是这样写的.为什么?好的加50!一楼的只回答了2个！另外，worry不是动词吗？ he wanted to find a seat to sit down还是sit on?不管上一个句子用哪一个,为什么he entered the lecture hall hoping to find a seat to sit on这个句子用sit on而不是down, She sat down这里的down是副词 那谓语是sit还是sit down吖 She came in 这里的谓语是came还是came in吖 please,sit down中的down是介词还是副词?为什么会出现sit down on one of these chairs这类结构? 与have a seat相近的词与这个词语相近的到底是sit 还是sit down? 是sit down at the table还是sit down beside the table答案是选AT,可是用beside可不可以呢 sit的过去式是sat还是sit What about____(sit)down and____(share)the cake with____(he)/ He sits down and had a test,还是把sits的s去掉? 助动词后面所有动词都要原型吗比如：Did they sit down under a big tree and ( ) a chat括号里面加have还是had 英语高手进,请给出答案并简单讲解,谢谢!1.Hardly____when a visitor came in. A. he had sat down B. did he sit down C he sat down D. had he sat down2.---Is there anything wrong, Bob? You look sad. ---Oh, nothing much! In fa “sit down”是一个祈使句还是一个短语呢?还有补充说明一下短语与词组有什么区别? When he hurried to the airport,the plane had-- 急!A.taken down B.taken off 请说明还是说一下好了，老师说选taken down 我不知道为什么...明天考是 快啊 His car broken down,he had to walk.是从句,还是分词短语?His car broken down 有主语和谓语动词,但是时态好像不对.怎么分析这句的结构?