I. -'s 1 /z, s/ BrE AmE
1 . the short form of ‘is’:
John’s here.
What’s that?
She’s writing a letter.
2 . the short form of ‘has’:
Polly’s gone out.
A spider’s got eight legs.
3 . a short form of ‘us’ used only in ‘let’s’
4 . spoken a short form of ‘does’, used in questions after ‘who’,‘what’ etc that many people think is incorrect:
How’s he plan to do that?
II. -'s 2 BrE AmE suffix
1 . forms the ↑ possessive of singular nouns, and of plural nouns that do not end in -s:
my sister’s husband
Mary’s generosity
yesterday’s lesson
the children’s bedroom
2 . British English the shop or home of someone:
I bought it at the baker’s (=at the baker’s shop) .
I met him at Mary’s (=at Mary’s house) .