it is not的缩写是it isn`t还是it`s not?

it is not的缩写是it isn`t还是it`s not?
it is not的缩写是it isn`t还是it`s not?

it is not的缩写是it isn`t还是it`s not?
it isn't

It's not

差不多，都一样

前面那个

it's not

都是的.都可以用.

it isn't