There are a lot of different types of questions on ACT English and SAT Writing and Language, but most of them are designed to test your ability to recognize writing that upholds the three C's: Consistent, Clear and Concise. One particularly tricky and common element that falls into the concise category is the use of apostrophes.

Apostrophes have two uses: possession and contraction. Here's a look at each, including how to spot them and how to correct them (if needed) on the test.

Possession = Apostrophes + Nouns

To show possession with a single noun, an 's is added to the end. With plural nouns, just the apostrophe is added. Here are two examples:

The new book of Marshall = Marshall's new book

The team of the boys = the boys' team

However, there are some tricky plurals that do not end in s, and therefore the same 's is necessary:

The team of the women = the women's team

Now, this only goes for nouns themselves, not for their pronoun counterparts. Instead of using an apostrophe with a pronoun, you'll use specific possessive pronouns:

His new book

Their team

If a question on the ACT or SAT is indicating possession using any method other than these, you can know without a doubt it needs correction. Similarly, if you encounter a different method of indicating possession in an answer choice, you can rule it out right away. Be warned, though, that apostrophes can be used in conjunction with pronouns, but they result in something entirely different than possession.

Contractions = Apostrophes + Pronouns

A pronoun with an apostrophe creates a contraction. I'm sure you've seen this before, a situation where the apostrophe takes the place of at least one letter. For example, in the previous sentence, “I'm" means “I am," and the apostrophe is standing in for the a, making two words into one (and therefore being more concise). Here are a few more examples:

They are doctors = They're doctors

Who is going to the movie? = Who's going to the movie?

They have won = They've won

Sound straightforward? That's what the tests wants you to think! But as with any section, be on the lookout for traps!

To start, say the contractions from these examples out loud. When said out loud and out of context, you're unsure how to spell them properly, aren't you? That's because these particular contractions sound the same as some possessive pronouns: They're/their/there; who's/whose; it's/its. That means that while on other questions you might be able to rely on your ear to spot an error, for these you'll have to know the rules I've laid out above.

For example, check out the following question:

When Julius Caesar's armies landed on British shores in 55 BCE, neither there language nor that of the local inhabitants bore any relation to what would eventually become English.

A) NO CHANGE

B) their

C) they're

C) its

If you try to use your ear, you'll get stuck because A, B and C all sound identical. (And D sounds pretty good here as well). However, if you know the rules, you'll see that you need a possessive form of the pronoun because the “language" is possessed by “Julius Caesar's armies," and you can eliminate A (which refers to a place) and C (which is “they are"). Finally, “Julius Caesar's armies" is plural, so you'll need the plural possessive, which is “their."

ACT and SAT English are far from being comprehensive, meaning the makers set out to test you on very specific tasks, and spotting the misuse of apostrophes is one of them. That's why I recommend studying up on all of the elements tested in this section before you sit down on test day. Take a practice test to know what you're able to spot easily and what causes you trouble. Plus, check out our books Cracking the ACT and Cracking the SAT for more breakdowns of each section.