We use contractions (I’m, we’re) in everyday speech and informal writing. Contractions, which are sometimes called ‘short forms’, commonly combine a pronoun or noun and a verb, or a verb and not, in a shorter form. Contractions are usually not appropriate in formal writing.
We make contractions with auxiliary verbs, and also with be and have when they are not auxiliary verbs. When we make a contraction, we commonly put an apostrophe in place of a missing letter.
The following are the most common contractions.
’m = am (I’m)
’re = are (you’re, we’re, they’re)
’s = is and has (he’s, she’s, it’s)
’ve = have (’ve, you’ve, we’ve, they’ve)
’ll = will (I’ll, you’ll, he’ll, she’ll, it’ll, we’ll, they’ll)
’d = had and would (I’d, you’d, he’d, she’d, it’d, we’d, they’d)
The contraction for not is n’t:
are not (we aren’t, you aren’t)
did not (I didn’t, they didn’t)
is not (she isn’t, it isn’t)
We use contractions with be + negative in two ways:
She is not is contracted to she isn’t or she’s not. I am not is only contracted to I’m not. Not: I’m n’t or I am n’t . They are not is contracted to they aren’t or they’re not. The isn’t / aren’t contractions are more common after nouns. The ’s / ’re not contractions are more common after pronouns: The cakes aren’t ready yet. She’ s not a friend of mine.
Contractions can occur after nouns, names, here, there and now and question words. These contractions are not considered appropriate in formal writing:
My sister has got married.