- A+
1. be 动词的形式有如下几种：
be / is / am / are / was / were / being / been
他们分别在句子当中呈现方式，我们举例说明：
The man is back.They are back.He was back.They were back.They have b
een back.2. be 动词的用法：
be动词在句中起到联系作用，be动词后面接名词、形容词、地点副词或短语作补足语。
举例说明一下：
The man is a teacher.Mary's new dresses are colorful.My mother was in the kitchen.They are teachers.He was a teacher before.He has been a teacher for 3 years.二、be动词的否定/提问/回答：
be动词的否定在is / am / are / was / were 后面加not.缩写形式：isn't / am not / wasn't / weren't
举例说明：
The man isn't back.I am not back.They aren't back.He wasn't back.They weren't back.2.使用be动词提问和回答：
1.-Is he a teacher?
-Yes, he is./No,he isn't.
2.-Are you a teacher?
-Yes, I am./No, I am not.
3.-Were they teacher?
-Yes, they were./No, they weren't.
练习(翻译)：
他是医生吗？Is he a doctor?不，他不是。No, he isn't.他们昨天在教室吗？Were they in the classroom yesterday?是的，他们在。Yes，they were。他们昨天不在教师。They weren't in the classroom yesterday.
