In most cases, when "not" is contracted with another word it becomes "-n't." e.g. Isn't, Hasn't.
you're
OK, here are some examples. He is or he has = he's. I have = I've. You can't always make contractions 'Is' and 'has' have no contractions by themselves
She's and He's
Isn't is a contraction for is not Hasn't is a contraction for has not
Mostly it depends on the organism of the pregnant woman (some contractions begin day and a half before and some don't even have contractions) but usually they occur in less than 20 hours before giving birth.
contractions
contractions come after non-contractions: Aunts Aunt's
Most contractions include a verb form, as in he's (he is) or they'd (they had) or can't (cannot). But some contractions (little = l'il) simply omit letters.
There are several contractions which combine not with another word. Some examples include won't, wouldn't, shouldn't, couldn't, haven't, hasn't, and aren't.
These can be muscle contractions or spasms.
we'll she'll he'll they'll it'll
Umm. . . contractions.