在英语语法中，什么时候用动词不定式表被动关系

动词不定式 　　I. 要点　　1、 不定式的形式。以动词write为例。 　　式｜语态 主动语态 被动语态 　　一般式 to write to be written 　　完成式 to have written to have been written 　　进行式 to be writing 　　完成进行式 to have been writing 　　2、 不定式的句法功能　　(1) 作主语　　To hear from you is nice.　　To be a good teacher is not easy.　　不定式作主语时，为了保持句子的平衡，往往以it作形式主语，而不定式置于谓语动词后。如：It's nice to hear from you.　　It's not easy to be a good teacher.　　(2) 作宾语　　通常用于want, hope, wish, like, need, hate, begin, start, remember, agree, learn, pretend, refuse, manage, help等词后。如：I forgot to lock the door.　　Please remember to write to me.　　(3) 作表语　　My job is to pick up letters.　　He seemed to have heard nothing.　　(4) 作定语　　不定式作定语时，须放在它所修饰的名词或代词后。如：　　I have two letters to write.　　I have a lot of work to do.　　(5) 作宾补　　通常用于want, wish, ask, order, tell, know, help, advise, allow, cause, force等词后。如：　　He ordered her to leave at once.　　He was forced to obey his order.　　(6) 作状语　　He got up early to catch the first bus.　　He worked hard to catch up with the other students.　　(7) 作独立成分　　To tell you the truth, I told a lie.　　(8) "疑问词＋不定式"结构。 如：　　I don't know how to choose them.　　I cannot decide where to go.　　(9)不定式的否定式。如：　　I decided not to go.　　(10)不定式的完成式。如：　　He seemed to have cleaned the room before I came in.　　The boy is said to have been sent to the hospital last week.　　(11)too…to 结构。如：　　He was too excited to go to sleep.　　He was only too glad to go. (他太高兴了，乐意去)　　(12)主动表被动。如：　　The book is easy to read.　　I have a book to read.

当不定式作宾语时，与主语之间是被动关系，就用被动The room needs to be cleaned.不定式作补语，与所补充的词之间是被动关系，就用被动I want the work to be done当不定式作定语时，与所修饰的词之间是被动关系，就用被动The meeting to be held tomorrow is very important.不定式作状语时，与句子主语之间是被动关系，就用被动In order to be chosen,she practiced a lot before the niterview.

如果你有家里人有上高三的，可以问一下他们，或者也可以问一下老师