-'s We use -'s (apostrophe + s) mostly for people or animals:
Tom's computer isn't working. (not the computer of Tom)
How old are Chris's children? (not the children of Chris)
What's your sister's name?
What's Tom's sister's name?
Note that you can use -'s without a following noun:
This isn't my book. It's my sister's. (= my sister's book)
. We do not always use -s' for people. For example, we would like use of... in this sentence:
What was the name of the man who phoned you? ("the man who phoned you" is too long to be followed by -'s)
Note that we say a women's hat (= a hat for a women), a boy's name (= a name for a boy), a bird's egg (= an egg laid by a bird) etc.
With a singular noun we use -'s:
my sister's room (= her room - one sister)
With a plural noun(sisters, friends etc.) we put an apostrophe at the end of the word(-'s):
my sisters' room (= their room - two or more sisters) If a plural noun does not end in -s (for example man/women/children/people) we use -'s:
the men's changing room
Note that you can use -'s after more than one noun:
Jack and Karen's wedding
For things, ideas etc., we normally use of(... of the book/... of the restaraunt ect.):
the door of the garage (not the garage's door)
the name of the book
You can usually use -'s or of... for an organisation (= a group of people). So you can say:
the government's decision or the decision of the government
It is possibly to use -'s for places. So you say:
the city's streets You can also use -'s with time expression:
Do you still have yesterday's newspaper?