Be 动词的形式

be ,  is ,  am , are , was , were , being , been 

 is ,  am , are :  一般现在时的be动词

1.The man is back 

2.They are back

was , were ： 过去时态 的be动词

3.He was back

4.They were back

being ：be动词的现在分词

been : be动词的过去分词 

5.They have been back

Be动词的用法（后面接名词，形容词，地点副词或短语作补足语）

  The man is  a teacher

   Mary's new dresses(dress)  are colorful

   My mother was in the kitchen 

Be动词的练习

1.他们是老师（they， teacher）

They are teachers

2.他以前是一名老师（he ， a teacher , before）

He was a teacher before

3.他已经当了3年的老师。（for 3 years）

He has been a teacher for 3 years