1. Be动词有三个，am,is还有are.我用am, 你用are, is跟着他她它，复数全部都用are.

　　如果遇到过去时，was来把am,is替，were来把换掉动词are

　　2. do和be动词的用法区别

　　Be 动词就是(am，are,is)..句子中如果没有实意动词(例如:write，buy)之类的动词，就直接在主语后面加Be动词。而如果是句子中有实意动词，那么如果你要改为一般疑问句，就要借助DO(do也称为助动词)，例如:I study.

　　改为一般疑问句:Do you study ?

　　顺口溜：be氏三朵花, am, is还有are,

　　我(I)恋am, 你(you)恋are,

　　is跟了他(he)她(she)它(it),

　　单娶is, 复娶are。

　　2、在句子中，be有两种主要作用：一是作为系动词(The Linking Verb)，本身可以作用谓语动词；二是做为助动词(The Auxiliary Verb)，与谓语动词一起构成各种时态和被动语态等。

　　下面做个简要的讲解。

　　一、be 动词做系动词

　　1、系动词+表语”的结构

　　当be 动词做系动词使用时，主要构成“系动词+表语”的结构，在句子中做谓语。表语可以是名词、形容词、副词、介词短语等。例如：

　　The man is a science teacher.

　　Mary's new dresses are colourful.

　　Mother is in the kitchen now.

　　I have been there before.

　　They shall be here at 10:00 tommorow.

　　That can't be true.

　　You are not being very polite.

　　Your brother is being very annoying this evening

　　2、be 动词的一般疑问句，方法是把be 移到主语前面，也可说成是移到句首。

　　Is the man a science teacher? Yes, he is. / No, he isn't.

　　Are Mary's new dresses colourful? Yes, they are. / No, they aren't.

　　Was mother in the kitchen then? Yes, she was. / No, she wasn't.

　　Were you at home the day before yesterday?  Yes, I was. / No, I wasn't.

　　Was she late this morning? Yes, she was. / No, she wasn't.

　　详细讲解：

　　英语的be 动词是个用法比较复杂的动词。复杂的原因有两点：

　　1、 除了原形的 be 之外，对于不同人称代词以及单数名词和复数名词，be 会有各种变化形式和缩写形式。概括一下有七种形式：be, am, is, are, was, were, been, being。它们与人称代词和名词单、复数的搭配关系是：

　　现在时 I am, you are, he/she/it/ is, we/you/they are；名词单数、不可数名词用is，复数用are。

　　缩略式 I'm, you're, he's, we're, you're, they're

　　否定缩略式 I'm not, isn't, aren't

　　过去时 I was, you were, he/she/it/ was, we/you/they were；名词单数、不可数名词用was，复数用were。

　　否定缩略式 wasn't, weren't

　　过去分词 been

　　现在分词 being

　3、be 动词用在特殊疑问句

　　在特殊疑问句里，be 动词仍然移到主语前面，但特殊疑问句是以特殊疑问词开头的，所以be 动词只能说是移到主语前面，或者说是在特殊疑问词的后面。例如：

　　Whose bike is broken? Xiao Ming's bike is.

　　Who was singing in the room? Mr. Zhang was.

　　Where are you from? I am from Wuhu.

　　What class were you in? We were in Class 2.

　　How old is Tom? He is ten.

　　4、be 动词的否定句

　　be 动词做谓语时，它的否定形式是在be 后加not，并且可以缩写。例如：

　　It is not sunny today.

　　Tom and his friends are not in the park.

　　You were not nine years old when I went to the university.

　　He was not often late for his class when he was a student.

　　I wasn't here yesterday.

　　My parents weren't at home last Sunday.

　　5、be 动词的祈使句

　　be 动词的祈使句有肯定和否定两种形式。肯定形式是以be 动词开头，而否定形式或强调句形，要加don't 或do。例如：

　　Be careful!

　　Be a good boy!

　　Don't be silly!

　　Don't be a fool!

　　Do be obedient!

　　Do be careful.