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
1600s • Arrives in English
1700s • Shows Possession
Today • SHSAT Tests It
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
Singular Possession = 's
Plural Possession = s'
Never Use Apostrophes for Regular Plurals
KEY TAKEAWAY
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.
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
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.
| 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. |
Common apostrophe traps on the SHSAT
Quick Substitution Test
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)
Step-by-Step Fix
- 1
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 - 2
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 - 3
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 - 4
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 - 5
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
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.
| ✗ 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. |
Side-by-side comparison of common apostrophe mistakes
KEY TAKEAWAY
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.
| 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. |
Current skills vs. advanced apostrophe concepts
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?
Question 1: CONCEPTUAL
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Question 2: BASIC
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Question 3: INTERMEDIATE
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Question 4: APPLIED
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Question 5: CRITICAL THINKING
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SUMMARY
Apostrophe Usage — Quick Review
Summary
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.