be动词的形式和用法

Be动词的形式： be, is, am, are, was, were, being, been

1.The man is back
2.They are back
3.He was back
4.They were back
5.They have been back

be动词的用法 后面接名词，形容词，地点副词，或短语做补足语

1.The man is a teacher
2.Mary's new dresses are colorful
3.My mother was in the kitchen

be动词的否定，在am, is, are, was, were 后面加 not, 缩略式am not, isn't, aren't, wasn't, weren't,

1.The man isn't back
2. I am not back
3. They aren't back
4. He wasn't back
5. They weren't back

使用be动词提问和回答

1. Is he a teacher?
    Yes, he is (a teacher 省略回答) / No, he isn't
2. Are you a teacher?
    Yes, i am / No, i am not
3.Were They Teachers?
    Yes, they were / No, they weren't