这节课开始我们来学 grammar 语法，是 the basic grammar（基础的语法），请大家酌情学习~

(to) be 动词

I am
You are
He / She / It is  (*it可以指动物、植物、各种物体、天气等等)
We are
They are

注意：you 可以是一个人“你”，也可以是多个人“你们”；可以是“你”，也可以是“您”。

否定（Negative）
I am not (I'm not)
You are not (You aren't)
He is not (He isn't)
She is not (She isn't)
It is not (It isn't)
We are not (We aren't)
They are not (They aren't)

问句（Question form）
Am I …?
Are you …?
Is he / she / it …?
Are we …?
Are they …?

简短回答 （Short answers）
Yes, I am / No I'm not
Yes, you are / No you aren't
Yes, he, she, it is / No he, she, it isn't
Yes, we are / No we aren't
Yes, they are / No they aren't

此部分资料来源：

english-at-home.com/grammar

dictionary.cambridge.org/grammar/british-grammar

www.merriam-webster.com

www.collinsdictionary.com