# The Negative of a statement is formed by the use of an auxiliary verb with the negative not.

(I sleep not, and similar expressions are found only in poetry etc.)

# The Interrogative of a statement is formed by the use of an auxiliary verb at the beginning of the sentence.

# In conversation the auxiliary verb and the negative not are often contracted into one syllable.

Aren’t, (ain’t*), won’t, can’t, shan’t, mayn’t, don’t, weren’t. But Isn’t, couldn’t, wouldn’t, shouldn’t, hasn’t, haven’t, wasn’t, doesn’t, didn’t, mightn’t, needn't, oughtn’t, are two-syllable words.

It is not becomes It’s not or It isn’t.

I am not becomes I'm not.

You are not becomes You aren’t or You're not.

(Informal) ain’t* = is not, are not, am not, has not, have not.