Punctuation - when to use apostrophes

Common Errors: Punctuation - when to use apostrophes

Some common errors exams students make with apostrophes:

My friends laptop

My friend's laptop

These students names are all difficult to pronounce.

These students' names are all difficult to pronounce

Is that book your's?

Is that book yours?

Look at the tiger. It's fur is orange with black stripes.

Look at the tiger. Its fur is orange with black stripes.

Youre late!

You're late!

I don't buy CD's now. I buy all my music on-line.

I don't buy CDs now. I buy all my music on-line.

I don't like music from the 1980's

I don't like music from the 1980s. 

When do I use an apostrophe?

1) We use an apostrophe followed by an s to show possession (to show that something belongs to something else).

The child's toys were lying all over the floor.

The bank's offices are in the centre of London.

When the person or thing that is doing the possessing is plural, we put the apostrophe after the final s.

The players' boots were covered in mud.

The girls' shoes were the same colour.

We never use an apostrophe with possessive pronouns: yours, his, hers, its, ours, theirs.

Look at that bird. Its feathers are beautiful. (NOT: Look at that bird. It's feathers are beautiful.)

Are these seats ours? (NOT: Are these seats our's?)

2) In informal writing we use contractions. We use apostrophes to indicate the contractions - to show where the missing letters are.

He's been studying English for a year. (He has been studying English for a year.)

We're going on holiday to Florida next week. (We are going on holiday to Florida next week.)

3) We don't use an apostrophe to show the plural of abbreviated words.

My suitcase weighs 30 KGs! (NOT: My suitcase weighs 30 KG's!)

I have two PCs and a laptop at home. (NOT: I have two PC's and a laptop at home.)

4) We don't use an apostrophe in the plural of dates and numbers.

In the 1940s (NOT: In the 1940's)

He's been working for this company since the seventies. (NOT: He's been working for this company since the seventie's.)

More common errors