be动词的缩写口诀如下：
基本形式
我（I）用am
你（you）用are
他（he）用is
她（she）用is
它（it）用is
单数名词用is
复数名词用are
缩写形式
I'm = I am
You're = you are
He's = he is
She's = she is
It's = it is
We're = we are
They're = they are
否定形式
is not 缩写为 isn't
are not 缩写为 aren't
疑问形式
变疑问时，be动词提前，句尾加问号
特殊用法
this与is, these与are
希望这些口诀能帮助你更好地记住be动词的用法和缩写形式。