Two jobs, one mark: apostrophes

What does an apostrophe do?

Two entirely separate things, and almost every mistake comes from confusing them.

It stands in for missing letters. Do not becomes don't. Cannot becomes can't. The apostrophe marks the gap where the letters were.

It shows belonging. The dog's lead. Nothing is missing here; the mark is doing a completely different job.

So the first question is never where does the apostrophe go? It is which job is it doing?

Missing letters

The easier of the two, and worth doing first because it makes the other one clearer.

Read the word out in full. If it expands — don't to do not, she'll to she will, it's to it is or it has — then letters are missing and the apostrophe sits exactly where they were.

That expansion test also settles the most contested apostrophe in English, which we will come to.

Belonging

Here the apostrophe's position carries meaning, and it is meaning a reader depends on. The reliable way to place it is to write the owner first, then add the ending.

One owner: add apostrophe and s. The girl's coat — one girl.

A plural owner that already ends in s: add the apostrophe alone. The girls' coats — several girls.

A plural owner that does not end in s: add apostrophe and s. The children's books, the men's race.

So an apostrophe before the s does not always mean a single owner. Children's has it before the s, and there is more than one child.

The diagram lines the three cases up, owner first.

The one that takes no apostrophe

Its shows belonging and has no apostrophe at all.

That looks like an exception until you notice the company it keeps: his, hers, ours, theirs, yours — none of them take one either. Possessive pronouns simply do not.

It's, with the apostrophe, is the shortened form of it is or it has.

Test it by expanding both ways: the dog wagged it is tail and the dog wagged it has tail are both nonsense, so it is its. Where an expansion works — it's raining (it is), it's stopped (it has) — the apostrophe belongs.

Where do pupils lose marks?

Apostrophes in ordinary plurals. Fresh apple's is the national error, and nothing belongs to the apples.

Placing the mark before working out the owner, which turns the question into a coin toss.

Writing it's for the possessive, which the expansion test catches every time.

Try it yourself

For each one, say which job the apostrophe is doing — missing letters or belonging — before you place it.

1. Punctuate: The girls coats were left in the hall. (several girls)
2. Punctuate: The girls coat was left in the hall. (one girl)
3. Which is right: 'The dog wagged its tail' or 'The dog wagged it's tail'?
4. Punctuate: The childrens playground was closed.
5. What is wrong with a market sign reading: Fresh apple's, £2 a bag.

Show Answers

How much practice does this type need at home?

Read signs. Genuinely — greengrocers, pub chalkboards, handwritten notices in shop windows. Apostrophe errors are everywhere, and spotting them in the wild teaches more than a worksheet because your child has to notice the mark before judging it.

Ask two questions each time: which job is it doing, and who is the owner? A child who asks those in that order will get this right for life, not merely for the test.