英语缩写单词有哪些?

那我就列举一些常用的吧.
1) 系动词/助动词/情态动词的否定式的缩写
is not - isn't
do not - don't
does not - doesn't
did not - didn't
have not - haven't
has not - hasn't
had not - hadn't
must not - mustn't
should not - shouldn't
shall not - shan't
will not - won't
2) 主语与系动词/助动词/情态动词的缩写
I am - I'm
You are - You're
He is - He's
She is - She's
We are - We're
They are - They're
It is - It's
3) 一些代词/介词/名词的缩写
something - sth.
somebody - sb.
without - w/o
telephone - tel.
please - pls.
quantity - q'ty
piece - pc
company - co.
limited - ltd.
on behalf of - o/b