gotta的用法

There's gotta be something wrong with you.
= There has got to be something wrong with you.

A man's gotta look out for his family.
= A man has got to look out for his family.

以上两则指的都是 "has got to" 这个句型，因此短写成 "'s gotta"。

I gotta go home.
= I got to go home.

gotta=got to (相当于have to 不得不，必须)
There's something I gotta tell ya我有点事要和你说.
I've gotta get outta here.我得离开这儿了。

have got to be?应该是have gotten to be吧。