TEST: Expand the contractions it’s, don’t, and can’t to be it is, do not, and cannot. Determine if the word with the apostrophe is supposed to be plural, then determine if this word is possessing the next word.

Use an apostrophe to create the possessive form of a noun.

An apostrophe is used before an s to create the possessive form of singular nouns and plural nouns that don’t already end in s.

The boy’s face was covered with mosquito bites when he returned from camp.

In this example, the boy possesses his own face, so the apostrophe is correct.

The team members’ jerseys were covered with mud after the game.

In this example, the members (all of them together) possess the jerseys.

If you see something like:

A) world’s oceans
B) worlds’ oceans
C) worlds oceans
D) worlds’ oceans’

the first step should be to think, “Do I have one world or many?” and then eliminate answers based on that. The second step should be, do the worlds possess their oceans? This should get you to the correct answer quickly.

Note that answers that look like D, with two possessives in a row, will always be wrong.

The exception to this rule is “it”. The possessive form of it is its.

its = possessive
it’s = it is
its’ = this will never be right!

Use an apostrophe in a contraction to indicate that one or more letters have been omitted.

We can’t [cannot] use the school swimming pool on weekends. It’s [it is] getting late out.