Question

Gostaria de uma explicacao de como devo utilizar o do, doesn't , isn't e aren't.

Answer 1

Do e doesn't são auxiliares quando se usa o presente simples com verbos que não sejam o verb to be.

Do you go to school?
Yes, I do.
Doesn't she like apple?
No. She doesn't like apple.

O isn't (he, she, it) e o aren't (you, we, they) são o próprio verb to be na negativa.

He isn't a good guy.
They aren't good people.
We aren't happy.

espero ter ajudado.