These probably cause more grief and despair than any other form of punctuation.
Yet they are not really that difficult. Honestly. Just concentrate a bit and
An apostrophe is the punctuation mark which appears at the top of the line – as in it's, or hasn't or Michael's.
There are only two kinds of apostrophes.
The first indicates a missing letter.
The second indicates possession: that someone or something owns something else.
The first – as in it's, or hasn't indicates a missing letter. It's a shortening, a contraction. Instead of writing it is, we write it's. The apostrophe indicates the missing 'i'.
Instead of writing has not, we write hasn't. The two words are joined, and the apostrophe indicates the missing 'o'.
So we get:-
could not couldn't
would not wouldn't
will not won't
should not shouldn't
shall not shan't
have not haven't
has not hasn't
do not don't
did not didn't
it is it's
is not isn't
You will also see such things as 'y'know', where the apostrophe indicates the letters missing from 'you know'.
'I will' becomes 'I'll'
'You will' becomes 'you'll' – and so on.
THE POSSESSIVE APOSTROPHE is used in such sentences as:
Are those Michael's children?
Did you take Aysha's toy?
I'll give you Daddy's book.
In the first sentence, the children belong to Michael, and the apostrophe indicates this.
In the second, the toy belongs to Aysha, even though it's been taken.
In the third sentence, there is both a contraction apostrophe and a possessive one. The 'I will' at the start has been contracted to 'I'll'. The book belongs to Daddy, and so an apostrophe and an 's' is added.
THE ORIGIN OF THE POSSESSIVE APOSTROPHE.
It may help to remember when and where to put an apostrophe if you remember why they were first used.
Before 1500, possession was indicated in English rather like this:-
You are summoned to the King, his house...
Go and saddle the Lord, his horse...
You should pay the man his wage...
After some time, this was shortened to:-
You are summoned to the Kingis house...
Go and saddle the Lordis horse...
You should pay the manis wage...
But this could be confusing. What is a 'manis'? So it began to be written as it was pronounced, and with an apostrophe to indicate that a letter was missing. This made it clear that the word was not 'manis' but 'man's.
And so we got:-
You are summoned to the King's house...
Go and saddle the Lord's horse...
You should pay the man's wage...
So, in a way, the 'possessive apostrophe' is a 'contraction apostrophe' too, but used in a special way, to indicate ownership. The house belongs to the King, the horse belongs to the Lord, and the wage belongs to the man (even if it hasn't been paid yet.)
But you don't have to be a person to get a possessive apostrophe -
The cup's handle...
The book's pages
The computer's screen
The phone's ring-tone.
The handle belongs to the cup, the pages belong to the book, the screen belongs to the computer...
Even untouchable abstracts can own things -
Beauty's truth lives forever...
Love's turbulent ways...
THE PROBLEM WITH PLURALS
A mistake commonly made with possessive apostrophes occurs with plurals.
'The book's pages...' This is talking about one book with many pages. The 's' at the end of 'pages' tells us that there is more than one page in this book.
'The books' pages...' Look at where the apostrophe is. This means we are talking about the pages in more than one book.
'The computer's screen' – one computer, one screen.
The computers' screens – many computers, many screens.
The car's horn – one car, one horn
The cars' horns – many cars, many horns.