入门：主—系—表
主—系—表
主—be—表
be-是（am is are）
一、陈述句：A是B。
am第一人称
I am at home.（I’m）
is第三人称（单数）
He is in the classroom.(He’s)
She is Lily.(She’s)
It is black.(It’s)
The dog is black.
are复数、第二人称
We are classmates.(We’re)
They are friends.(They’re)
You are beautiful.(第二人称)(You’re)
二、疑问句：be—主—表？
Am I at home？(不合理)
Are you at home？（合理）
Is she Lily？Yes, she is. Yes. She is.
Is he in the classroom? Yes, he is.
Is the dog black? Yes, it is.
Are you classmates? Yes, we are.
Are they friends? Yes, they are.
一般疑问句（回答是或否）
三、否定句（加not）
I am not at home.（I’m）
He is not in the classroom.( isn’t )
She is not Lily.( isn’t)
It is not black.( isn’t)
The dog is not black. ( isn’t)
We are not classmates.( aren’t)
They are not friends.( aren’t)
You are not beautiful. (aren’t)
am not不缩写
is not缩写为 isn’t
are not缩写为 aren’t
特殊疑问句（要求具体回答）
疑问词：where, what, who, why
He is in the classroom.
Where is he?
