Apostrophe Usage — Use apostrophes correctly for possession...

SECTION 1

Where Did the Apostrophe Come From?

Have you ever wondered why a tiny floating comma can cause so much confusion? The apostrophe (the mark that looks like this: ') has been part of written English for hundreds of years. It started out in other languages and slowly made its way into English writing. Understanding its history helps you see why it works the way it does today.

1500s

Born in France

French printers started using the apostrophe to show that a letter had been dropped from a word. The word apostrophe comes from Greek, meaning 'turning away' — as in turning away a letter.

1600s

Arrives in English

English writers borrowed the apostrophe to mark missing letters in contractions like it's (it is) and don't (do not).

1700s

Shows Possession

Writers began using the apostrophe to show ownership, too. Instead of writing 'the hat of the girl,' they could write 'the girl's hat.' This made sentences shorter and snappier.

Today

SHSAT Tests It

The SHSAT Revising and Editing section asks you to spot apostrophe errors in sentences. Knowing the rules means easy points on test day.

So the apostrophe has two main jobs: showing that letters are missing (contractions) and showing that something belongs to someone or something (possession). Let's break down both jobs so you can ace every apostrophe question on the SHSAT.

SECTION 2

Core Rules of the Apostrophe

Every apostrophe question on the SHSAT comes down to a handful of clear rules. Once you memorize them, spotting errors becomes almost automatic. Here are the four big ideas.

Contractions = Missing Letters

When two words are combined and letters are removed, an apostrophe takes the place of the missing letters. Example: cannot → can't. The apostrophe sits right where the missing letters used to be.

Singular Possession = 's

To show one owner, add an apostrophe and then the letter s. Example: the dog's bone means one dog owns the bone.

Plural Possession = s'

If the owner word is plural and already ends in s, just add an apostrophe after the s. Example: the dogs' bones means multiple dogs own the bones.

Never Use Apostrophes for Regular Plurals

A common mistake is writing apple's when you just mean more than one apple. If nothing is being owned and no letters are missing, leave the apostrophe out. Write apples.

✦ KEY TAKEAWAY

Think of the apostrophe like a little hook. It either hooks two words together (contractions) or hooks an object to its owner (possession). If the apostrophe isn't hooking anything, it probably doesn't belong there.

SECTION 3

Seeing the Apostrophe in Action

A picture is worth a thousand words. The diagram below shows how the apostrophe works in both contractions and possessives. Follow the arrows to see where the apostrophe lands and why.

The left column shows contractions — the apostrophe replaces missing letters. The right column shows possession — the apostrophe marks ownership. The red box at the bottom reminds you never to use an apostrophe just to make a word plural.

Look at the left column first. In each contraction, the apostrophe takes the exact spot where letters were removed. For example, in don't, the apostrophe replaces the o from not. Now look at the right column. The placement of the apostrophe tells you whether one thing or many things own something. If the word already ends in s because it is plural, you just tuck the apostrophe after that s.

SECTION 4

How Apostrophe Placement Works Step by Step

You don't need math formulas for this topic, but you do need a clear decision process. Think of it like a flowchart in your head. Every time you see (or need) an apostrophe, run through these checks.

Decision 1: Is it a contraction?

Ask yourself: are two words being combined into one? If yes, figure out which letters are being removed and put the apostrophe right there. Common contractions include isn't (is not), they're (they are), we've (we have), and who's (who is or who has).

Decision 2: Is it possession?

If a noun owns something, you need a possessive apostrophe. First, write the owner word completely. Then ask: does that word already end in s? If it does not, add 's. If it does (because the word is a regular plural), just add an apostrophe alone after the existing s.

Decision 3: Is it just a plural?

If nothing is being owned and no letters are missing, no apostrophe is needed. Adding one to a regular plural is a mistake test-writers love to include as a trap.

⚠ Watch Out: It's vs. Its

This is the number-one apostrophe trap on standardized tests. It's always means it is or it has (a contraction). Its (no apostrophe) means 'belonging to it' (possessive). Think of his, hers, its — none of these possessive pronouns use apostrophes.

Follow the arrows from top to bottom. At each question, go left for YES or right for NO. This flowchart covers contractions, singular possessives, plural possessives, irregular plurals, and plain plurals.

SECTION 5

Tricky Cases the SHSAT Loves to Test

The SHSAT does not just test easy apostrophes. It focuses on the mistakes that even good writers make. Let's look at the trickiest situations so you are ready.

Common apostrophe traps on the SHSAT

Tricky Pair	Rule	Example
it's vs. its	it's = it is / it has; its = belonging to it	It's raining. The cat licked its paw.
they're vs. their vs. there	they're = they are; their = belonging to them; there = a place	They're putting their bags over there.
you're vs. your	you're = you are; your = belonging to you	You're going to love your new school.
who's vs. whose	who's = who is / who has; whose = belonging to whom	Who's the student whose project won?
Singular names ending in s	Add 's (James's). Some style guides allow just an apostrophe; the SHSAT typically accepts 's.	James's locker is next to mine.

💡 Quick Substitution Test

Whenever you see it's, they're, you're, or who's in a sentence, try replacing it with the full two words. If the sentence still makes sense, the apostrophe is correct. If it sounds wrong, you need the non-apostrophe version.

For example, read this sentence: 'The team celebrated it's victory.' Replace it's with it is: 'The team celebrated it is victory.' That sounds terrible! So you need its (no apostrophe) because the victory belongs to the team.

SECTION 6

Worked Example — Fixing a Paragraph

On the real SHSAT, you will read a passage and choose the best way to fix underlined sections. Let's practice with a short paragraph that has apostrophe errors.

📝 Original Paragraph (with errors)

The student's were excited about the science fair. Each groups project had to include it's own hypothesis. Marias experiment used three plant's to test sunlight levels. She wanted to know who's results would be the strongest.

Step-by-Step Fix

Step 1 — Check 'student's'Ask: do the students own something here? No — the sentence says they 'were excited.' This is just a plain plural. No apostrophe needed.

Fix: students

Step 2 — Check 'groups project'Ask: does the group own a project? Yes — each group has its own project. 'Group' is singular here (each group), and it does not end in s, so add 's.

Fix: group's project

Step 3 — Check 'it's own hypothesis'Use the substitution test: 'it is own hypothesis' — that does not make sense. We need the possessive pronoun, which has no apostrophe.

Fix: its own hypothesis

Step 4 — Check 'Marias experiment' and 'plant's'Maria owns the experiment. She is one person, and her name does not end in s, so add 's. Meanwhile, 'plant's' is just a regular plural — nothing is owned — so remove the apostrophe.

Fix: Maria's experiment / three plants

Step 5 — Check 'who's results'Substitution test: 'who is results' — nope, that is nonsense. We need the possessive form whose, which shows belonging.

Fix: whose results

✅ Corrected Paragraph

The students were excited about the science fair. Each group's project had to include its own hypothesis. Maria's experiment used three plants to test sunlight levels. She wanted to know whose results would be the strongest.

SECTION 7

Common Errors vs. Correct Usage

Let's compare the most common apostrophe mistakes side by side. Seeing the wrong version next to the right version trains your eye to catch errors fast.

Side-by-side comparison of common apostrophe mistakes

✗ INCORRECT	✓ CORRECT	Why?
The boy's ran fast.	The boys ran fast.	Plain plural — no ownership, no missing letters.
The teachers desk is messy.	The teacher's desk is messy.	One teacher owns the desk → add 's.
All the teacher's desks are clean.	All the teachers' desks are clean.	Multiple teachers own desks → apostrophe after the s.
The childrens' game ended.	The children's game ended.	'Children' is already plural and doesn't end in s → add 's.
Your going to love this.	You're going to love this.	Contraction of 'you are' → you're.
The cat chased it's tail.	The cat chased its tail.	Possessive pronoun — no apostrophe, just like his or hers.

✦ KEY TAKEAWAY

Imagine you are a security guard at the apostrophe gate. Before you let an apostrophe into a word, it needs to show ID. Its ID should say either 'I'm replacing missing letters' or 'I'm showing that someone owns something.' If the apostrophe can't show either ID, turn it away!

SECTION 8

Looking Ahead — Advanced Apostrophe Skills

The rules you learned in this lesson cover everything the SHSAT tests. But as you move into high school, you will run into a few more apostrophe situations. Here is a quick preview.

Current skills vs. advanced apostrophe concepts

What You Know Now	What's Next
Singular names ending in s get 's (James's)	Some style guides (AP, Chicago) differ on this rule. You'll learn when to follow which guide.
Contractions join two words	In formal essays, many teachers ask you to avoid contractions entirely. You'll learn when informal tone is acceptable.
Possessive pronouns never take apostrophes	You'll explore possessive forms with gerunds (e.g., 'I appreciate your helping me') in advanced grammar.
Regular plurals never take apostrophes	One rare exception: plurals of single letters or numbers (e.g., 'Mind your p's and q's'). This is unlikely on the SHSAT.

For now, focus on the core rules. They will carry you through the SHSAT and into high school English. The more you practice spotting errors, the more automatic it becomes.

SECTION 9

Practice Problems

Try these five problems on your own before reading the answers. They get harder as you go. Remember your decision process: contraction, possession, or plain plural?

PROBLEM 1 — CONCEPTUAL

What are the two jobs that an apostrophe performs in English? Give one example of each.

PROBLEM 2 — BASIC

Choose the correct word: 'The two (girl's / girls / girls') shared a locker.' Explain your choice.

PROBLEM 3 — INTERMEDIATE

Fix all apostrophe errors in this sentence: 'Its clear that the three student's projects dont meet the teacher's standard's.'

PROBLEM 4 — APPLIED

Read this SHSAT-style sentence and pick the best revision for the underlined portion: 'The children's soccer teams uniforms were muddy after the game.'

PROBLEM 5 — CRITICAL THINKING

A classmate argues: 'Possessive pronouns like his and hers don't use apostrophes, but possessive nouns like Maria's do. That's inconsistent — English should pick one rule.' Is your classmate right that the rules are inconsistent? Why might English work this way?

SUMMARY

Apostrophe Usage — Quick Review

The apostrophe has exactly two jobs. First, it creates contractions by replacing missing letters when two words merge (do not → don't). Second, it shows possession: add 's for a singular owner (the girl's book), and add just an apostrophe after s for a regular plural owner (the girls' books). Irregular plurals that don't end in s (children, men, women) take 's just like singular nouns.

Watch out for the SHSAT's favorite traps: it's vs. its, they're vs. their, you're vs. your, and who's vs. whose. Use the substitution test: replace the contraction with its full form. If it sounds right, keep the apostrophe. If not, switch to the possessive pronoun (no apostrophe). Never use an apostrophe just to make a plain plural.