英语中be动词有哪些,他们分别怎么用?

英语的be动词有三个is am are 用法:助词 1。(与动词的现在分词连用,构成各种进行时态)正在。。。,在。。。I won't be free this afternoon。I'll be seeing a friend off。我今天下午没空,我要给朋友送行。What were you doing from 9 to 11 this morning?今天上午九点到十一点你在做什么?He is working。他在工作。2。(与及物动词的过去分词连用,构成被动语态)被。。。The problem was solved long ago。问题早解决了。It will be discussed tomorrow。此事将在明天讨论。3。【旧】(与不及物动词go,come,rise等的过去分词连用,构成完成时)已经。。。The sun is set。太阳已经下山。4。(与动词不定式连用,表示职责、义务、意图、约定、可能性等)应该做。。。,必须做 。。。;预定做。。。;会做。。。The President is to visit Japan next week。总统将于下周访问日本。You're to do your homework before you watch TV。你应该做了功课再看电视。不及物动词 vi。1。是[L] At that time he was the chair of the department。当时他是系主任。I am a teacher and they are my students。我是老师,他们是我的学生。She is very young。她非常年轻。2。(表示时间、度、量、价值等)是;值;等于[L] The watch is 100 dollars。这表值一百元。3。(常用祈使语气或不定式)要,得;成为;变成[L] Be quiet,please。请安静。4。(与there连用)有[L] There are a lot of tourists there。那里有许多观光客。5。逗留,(继续)呆[L] He will be here all next week。下周他将一直呆在这儿。6。在[Q] Tony is in the office。托尼在办公室里。7。存在 Whatever is has every reason for being。存在的东西总有其存在的理由。8。听任 If she's sleeping,let her be。如果她在睡觉,就别惊动她。 再问： 请问be可以直接用吗，有些填空里面答案不是am/is/are，而是be 再答： am is are 的区别 am只用在I 后面, 如 I am a girl 我是女孩 第三人称单数后面跟 is 如 He/She/It/Jim/is 其他跟 are, 如 They/we/girls/boys are 什么情况下用Be 借助外加助动词如do,did。或者在情态动词如can,will,would,could,should,may,might之后都必须使用be, 而不能直接用am is are。 例如，要说He can be a teacher。 而不能说 He can is a teacher。 同样的，He is a teacher 是正确的说法，He be a teacher 就是错误的说法了。