You really do need to study. Once you have, you can talk however the hell you want to, as your teacher has clearly demonstrated.

My english teacher would always talk like that too. If we talked like that, she would freak out.

Clearly she was mocking you. YDI

LOL that's irony for you :)

talking in an accent is something most people can turn on and off. we live in the south and my kids speech teacher has a thick accent when ypu are tak lkomg to her, but when she is working with the kids her speach is impeccable

IF your teacher did say that you should of went off about how she shouldn't be teaching .

Well actually "ain't" is a perfectly fine example of a colloquial contraction - it is not 'bad' English. Instead, it is just a use of the language in an informal, conversational manner. There is no "fml" here.

... Ain't is actually a word, short for "are not," so it actually works. Well, for the first one, at least. "You are not going to pass this class." The second maybe not. But it might be less mocking and more accent. In fact, it's entirely possible it wasn't intended to be mocking at all.

Ain't IS a word, and sadly it IS IN THE dictionary.

fun fact. ain't is a valid word.