Commonly Confused Words
Master its/it's, your/you're, there/their/they're, whose/who's, then/than, and affect/effect with quick substitution tests instead of guessing by sound.
What you'll do in this lesson
A voice-first session with the Crimsora tutor on Commonly Confused Words, then targeted practice and FRQs — with the tutor adapting to where you get stuck.
What this lesson covers
Say "its" and "it's" out loud. Identical. Now say "there," "their," and "they're." Also identical. That is exactly the problem: your ear is useless here, so if you write by sound alone you are basically flipping a coin. Readers notice, and in a research paper or a formal email the mix-up makes careful thinking look careless.
The good news is that none of these choices require memorizing a rule book. Each pair can be settled in about three seconds by swapping in a test word and listening to whether the sentence still makes sense. In this lesson you will learn one test for the apostrophe pairs, one test for then and than, and one test for affect and effect — plus how to spell the word you picked, since choosing "theirs" correctly and then writing "their's" undoes all your work.
The good news is that none of these choices require memorizing a rule book. Each pair can be settled in about three seconds by swapping in a test word and listening to whether the sentence still makes sense. In this lesson you will learn one test for the apostrophe pairs, one test for then and than, and one test for affect and effect — plus how to spell the word you picked, since choosing "theirs" correctly and then writing "their's" undoes all your work.
Your Ear Cannot Do This Job — A Test Can
Homophones are words that sound the same but differ in meaning and spelling. Because speech gives you no clue, the only reliable strategy is substitution: temporarily replace the confusing word with a test word and see whether the sentence still works.
Almost every pair in this lesson follows one of two patterns. Either one word is a contraction (two words squeezed together with an apostrophe standing in for missing letters) and the other is a possessive pronoun, or the two words belong to different parts of speech entirely.
For the contraction pattern, the test is to unsqueeze the word. Read the sentence with the full two words in place. "Its raining" becomes "It is raining" — that works, so the contraction it's is correct. "The dog wagged it is tail" is nonsense, so you need the possessive its.
For the part-of-speech pattern, ask what job the word is doing. Is it comparing two things, or telling when something happened? Is it an action, or a thing?
The second half of the job is spelling what you chose. A huge share of mistakes are not choice errors at all but spelling errors on possessive pronouns. Nouns take an apostrophe to show ownership — the dog's bowl, Maria's locker — but pronouns never do. His, hers, ours, yours, theirs, its, and whose are already possessive. Writing "your's" or "their's" or "it's dinner bowl" adds an apostrophe that has no letters to replace. If you can remember that one fact, you have removed a whole family of errors from your writing at once.
Run the test every single time. Even strong writers do not trust their ear on these words; they trust the swap.
Almost every pair in this lesson follows one of two patterns. Either one word is a contraction (two words squeezed together with an apostrophe standing in for missing letters) and the other is a possessive pronoun, or the two words belong to different parts of speech entirely.
For the contraction pattern, the test is to unsqueeze the word. Read the sentence with the full two words in place. "Its raining" becomes "It is raining" — that works, so the contraction it's is correct. "The dog wagged it is tail" is nonsense, so you need the possessive its.
For the part-of-speech pattern, ask what job the word is doing. Is it comparing two things, or telling when something happened? Is it an action, or a thing?
The second half of the job is spelling what you chose. A huge share of mistakes are not choice errors at all but spelling errors on possessive pronouns. Nouns take an apostrophe to show ownership — the dog's bowl, Maria's locker — but pronouns never do. His, hers, ours, yours, theirs, its, and whose are already possessive. Writing "your's" or "their's" or "it's dinner bowl" adds an apostrophe that has no letters to replace. If you can remember that one fact, you have removed a whole family of errors from your writing at once.
Run the test every single time. Even strong writers do not trust their ear on these words; they trust the swap.
The Apostrophe Pairs: its, your, their, whose
Four pairs work the same way. In each one, the word with an apostrophe is a contraction, and the word without one shows ownership. Memorize the tests, not the words.
There is the odd one out, since it is not possessive and not a contraction. It usually means a place ("put it there") or starts a sentence about existence ("There are twelve chairs"). A useful spelling hook: there contains the word here, and both are about place. Their contains the letters h-e-i-r, and an heir is a person who inherits — people own things.
Where students actually go wrong: they run the test on the easy sentence and skip it on the hard one. "Its been a long week" slips past because the sentence feels like it is describing something. Expand it — "It has been a long week" — and the missing apostrophe is obvious. The other frequent slip is writing the possessive with an apostrophe because possession usually needs one. Remind yourself that its, yours, theirs, and whose are pronouns, and pronouns are already possessive without help.
| Word | What it is | Swap in this | Example |
|---|---|---|---|
| it's | it is / it has | "it is" | It's cold. (It is cold.) |
| its | possessive | "his" | The team lost its lead. |
| you're | you are | "you are" | You're late. |
| your | possessive | "my" | Bring your notebook. |
| they're | they are | "they are" | They're waiting. |
| their | possessive | "our" | Their bus broke down. |
| there | place or opener | "here" | Sit over there. |
| who's | who is / who has | "who is" | Who's driving? |
| whose | possessive | "which person's" | Whose jacket is this? |
Where students actually go wrong: they run the test on the easy sentence and skip it on the hard one. "Its been a long week" slips past because the sentence feels like it is describing something. Expand it — "It has been a long week" — and the missing apostrophe is obvious. The other frequent slip is writing the possessive with an apostrophe because possession usually needs one. Remind yourself that its, yours, theirs, and whose are pronouns, and pronouns are already possessive without help.
Then and Than: Time Versus Comparison
These two are not even the same part of speech, which makes the test easy once you know what to look for.
Then is about time, sequence, or consequence. It answers when or what happened next. You will see it with words like first, next, after that, back then, and in if-sentences: "If the bus is late, then we walk."
Than is used for comparison. It appears after comparing words: bigger, faster, more, less, fewer, better, worse, rather, other, and any adjective ending in -er. "My backpack is heavier than yours."
The quick test: does the sentence compare two things? If yes, write than. If the sentence is telling when, write then. Try reading the sentence with "at that time" in place of the word. If it fits, you want then.
A spelling hook that works for most students: then and when both have an e and both deal with time. Than and compare both have an a.
This pair shows up constantly in casual texting, where "bigger then me" goes uncorrected, and that habit leaks into school writing. When you proofread, look specifically for any word ending in -er or the words more, less, or rather; the word right after them is almost always than. Do not rely on the sentence sounding fine, because both words sound nearly identical in fast speech and your brain will happily accept either one.
Then is about time, sequence, or consequence. It answers when or what happened next. You will see it with words like first, next, after that, back then, and in if-sentences: "If the bus is late, then we walk."
Than is used for comparison. It appears after comparing words: bigger, faster, more, less, fewer, better, worse, rather, other, and any adjective ending in -er. "My backpack is heavier than yours."
The quick test: does the sentence compare two things? If yes, write than. If the sentence is telling when, write then. Try reading the sentence with "at that time" in place of the word. If it fits, you want then.
A spelling hook that works for most students: then and when both have an e and both deal with time. Than and compare both have an a.
| Sentence | Correct word | Why |
|---|---|---|
| We ate, ___ we left. | then | sequence in time |
| She runs faster ___ I do. | than | comparison after "faster" |
| Back ___, phones had cords. | then | past time |
| I'd rather read ___ watch TV. | than | "rather" signals comparison |
Affect and Effect, and a Proofreading Routine
In everyday writing, affect is the verb and effect is the noun. Affect is what one thing does to another; effect is the result that follows. Many students use the memory phrase RAVEN: Remember, Affect is a Verb, Effect is a Noun.
Two swap tests confirm it. If you can substitute "influence," the word is affect: "Rain will affect the game" becomes "Rain will influence the game." If you can substitute "result," the word is effect: "The effect was dramatic" becomes "The result was dramatic." A second check is to put a, an, or the in front. Articles come before nouns, so "an effect," "the effect," and "side effects" are all correct, while "an affect" is almost never what a seventh grader means.
There are two rare exceptions worth knowing so they do not confuse you when you meet them. Effect can be a verb meaning to bring something about, as in "the mayor hoped to effect change," and affect can be a noun in psychology meaning an outward show of emotion. Neither belongs in most classroom writing, so stick with RAVEN.
When you proofread, do not reread for meaning and hope errors jump out — they will not, because your brain reads the word you intended. Instead, hunt for these specific words. Scan the draft once looking only for apostrophe pairs, run the expand test on each, and check that no possessive pronoun wears an apostrophe. Scan again for then, than, affect, and effect. Reading aloud slowly, with your finger under each word, slows you down enough to notice.
The payoff is bigger than clean punctuation. Sorting these words trains you to ask what job a word is doing in a sentence, and that question is the foundation of grammar work you will keep doing all year.
Two swap tests confirm it. If you can substitute "influence," the word is affect: "Rain will affect the game" becomes "Rain will influence the game." If you can substitute "result," the word is effect: "The effect was dramatic" becomes "The result was dramatic." A second check is to put a, an, or the in front. Articles come before nouns, so "an effect," "the effect," and "side effects" are all correct, while "an affect" is almost never what a seventh grader means.
There are two rare exceptions worth knowing so they do not confuse you when you meet them. Effect can be a verb meaning to bring something about, as in "the mayor hoped to effect change," and affect can be a noun in psychology meaning an outward show of emotion. Neither belongs in most classroom writing, so stick with RAVEN.
When you proofread, do not reread for meaning and hope errors jump out — they will not, because your brain reads the word you intended. Instead, hunt for these specific words. Scan the draft once looking only for apostrophe pairs, run the expand test on each, and check that no possessive pronoun wears an apostrophe. Scan again for then, than, affect, and effect. Reading aloud slowly, with your finger under each word, slows you down enough to notice.
The payoff is bigger than clean punctuation. Sorting these words trains you to ask what job a word is doing in a sentence, and that question is the foundation of grammar work you will keep doing all year.
Key terms
- Homophone.
- A word that sounds the same as another word but has a different meaning and usually a different spelling, such as their, there, and they're.
- Contraction.
- Two words shortened into one, with an apostrophe replacing the missing letters: it's (it is), you're (you are), who's (who is).
- Possessive pronoun.
- A pronoun that already shows ownership and therefore never takes an apostrophe: its, your, yours, their, theirs, whose, hers, ours.
- Substitution test.
- A proofreading move in which you swap a test word into the sentence to check your choice, such as replacing its with his or effect with result.
- Part of speech.
- The job a word does in a sentence — noun, verb, adjective, adverb, conjunction. Affect and effect, and then and than, are separated by their jobs.
- Comparison word.
- A word that signals two things are being measured against each other (bigger, more, less, better, rather). It is normally followed by than, not then.
- RAVEN.
- A memory phrase for the usual pair: Remember, Affect is a Verb, Effect is a Noun.
Worked example
Proofread this paragraph and correct every commonly confused word. "Our class went to the science museum, and its bigger then I expected. The guide told us that pollution can effect river animals in ways you're eyes cannot see. Their were tanks of fish along the back wall, and one student asked who's job it is to clean them. The affect of the whole trip was that I want to study biology."
Work word by word and run a test on each one instead of reading for the general sense.
"its bigger" — expand it: "it is bigger" makes sense, so this is the contraction. Correct to it's.
"bigger then I expected" — the word bigger signals a comparison, so the word that follows must be than.
"pollution can effect river animals" — try the swap: "pollution can influence river animals" works, and the word follows the helping verb can, so it is a verb. Correct to affect.
"you're eyes" — expand it: "you are eyes" is nonsense. The sentence needs the possessive, so write your.
"Their were tanks" — nothing is being owned here; the sentence announces that something exists. Swap in here: "Here were tanks" fits. Correct to There.
"who's job it is" — expand it: "who is job it is" is nonsense. You mean which person's job, so write whose.
"The affect of the whole trip" — the word follows The, and articles come before nouns. Swap in result: "the result of the whole trip" works. Correct to effect.
Corrected paragraph: "Our class went to the science museum, and it's bigger than I expected. The guide told us that pollution can affect river animals in ways your eyes cannot see. There were tanks of fish along the back wall, and one student asked whose job it is to clean them. The effect of the whole trip was that I want to study biology."
"its bigger" — expand it: "it is bigger" makes sense, so this is the contraction. Correct to it's.
"bigger then I expected" — the word bigger signals a comparison, so the word that follows must be than.
"pollution can effect river animals" — try the swap: "pollution can influence river animals" works, and the word follows the helping verb can, so it is a verb. Correct to affect.
"you're eyes" — expand it: "you are eyes" is nonsense. The sentence needs the possessive, so write your.
"Their were tanks" — nothing is being owned here; the sentence announces that something exists. Swap in here: "Here were tanks" fits. Correct to There.
"who's job it is" — expand it: "who is job it is" is nonsense. You mean which person's job, so write whose.
"The affect of the whole trip" — the word follows The, and articles come before nouns. Swap in result: "the result of the whole trip" works. Correct to effect.
Corrected paragraph: "Our class went to the science museum, and it's bigger than I expected. The guide told us that pollution can affect river animals in ways your eyes cannot see. There were tanks of fish along the back wall, and one student asked whose job it is to clean them. The effect of the whole trip was that I want to study biology."
Practice questions
Which sentence uses every underlined-type word correctly?
- The team celebrated it's win, then thanked they're coach.
- The team celebrated its win, then thanked their coach.
- The team celebrated its win, than thanked they're coach.
- The team celebrated it's win, than thanked their coach.
Answer: The team celebrated its win, then thanked their coach.
Test each spot. "Celebrated it is win" is nonsense, so the possessive its is right. The sentence tells what happened next in time, not a comparison, so then is right. "Thanked they are coach" is nonsense, so the possessive their is right. Only the second choice passes all three tests. Notice that the wrong versions all sound identical when read aloud, which is exactly why the swap test matters more than your ear.
Explain in your own words how you decide between whose and who's, and write one original sentence using each correctly.
Answer: Who's is the contraction of who is or who has, so it passes the expand test; whose is a possessive pronoun meaning belonging to which person, and like all possessive pronouns it takes no apostrophe. Sample sentences: "Who's bringing the poster board tomorrow?" (Who is bringing...) and "Whose calculator was left on the lab table?"
A complete answer names the expand-the-contraction test and states the reason whose has no apostrophe: pronouns are already possessive, so there are no missing letters for an apostrophe to stand in for. Students often explain the choice by saying whose "sounds more formal," but sound and formality are not the deciding factor — the grammatical job of the word is.
Rewrite this sentence correctly and explain each change: "The new bell schedule will effect you're afternoon classes more then the morning ones."
Answer: The new bell schedule will affect your afternoon classes more than the morning ones.
Three fixes. First, "will influence your afternoon classes" works, and the word follows the helping verb will, so the verb affect is needed. Second, "you are afternoon classes" is nonsense, so the possessive your is correct — and it takes no apostrophe. Third, the word more signals a comparison between afternoon and morning classes, so than replaces then. Nothing in the sentence involves time order, which is the only situation calling for then.
FAQ
- Does its ever take an apostrophe to show possession?
- No. Its is a possessive pronoun and never uses an apostrophe, the same way his, hers, ours, and theirs do not. The spelling it's always means it is or it has. Nouns are different — the dog's bowl needs an apostrophe — but pronouns already carry ownership built in.
- What is the fastest trick for there, their, and they're?
- They're expands to they are, so try reading the sentence with those two words in place. Their means belonging to them, so swap in our and see if it fits. There is left over for places and for openers like "there are." A spelling hook: there contains here, and both point to a place.
- Can affect ever be a noun or effect ever be a verb?
- Yes, but rarely, and almost never in seventh-grade writing. Effect as a verb means to bring something about, as in "effect change," and affect as a noun is a psychology term for a person's visible emotional state. Unless you specifically mean one of those, stick with RAVEN: affect is the verb, effect is the noun.
- Won't spell check catch these mistakes for me?
- Usually not. Every one of these words is spelled correctly on its own, so the software sees no error. Some grammar tools flag a few of them, but they miss plenty and sometimes suggest the wrong fix. Running the swap test yourself during proofreading is still the reliable method.
Learn this with a teacher, not a page
The Crimsora tutor teaches Commonly Confused Words live — explaining on a whiteboard, asking you questions, and adapting to where you get stuck.