20 Grammar Mistakes That Show Up on the SAT & ACT

Sentence B is correct. In A, your should be you’re (you are going to love…). In B, your correctly shows possession. Quick test: substitute you are — if it makes sense, use you’re. If not, use your.

A is correct. Their notes = possessive (notes belonging to them). They’re = they are (try substituting: “they are over there” — makes sense). There = a place. Three different words, three different jobs.

A is correct. Substitute it is: “The company lost it is top clients” — that’s nonsense. So the apostrophe doesn’t belong here. Its is a possessive pronoun. Possessive pronouns (his, her, our, their, its) never use apostrophes. The ACT tests its vs. it’s in almost every test.

B is correct. Substitute who is: “Who is backpack is blocking the aisle?” — doesn’t work. The sentence is asking about ownership (whose backpack belongs to whom), so the possessive whose is correct. Same logic as its vs. it’s.

A is correct. A is making a comparison (higher score vs. previous score), so than is correct. B compares nothing — it’s describing a sequence of events in time, so it needs then (she studied, then took a test). If you can replace the word with “next” or “at that time,” use then.

B is correct. Alot does not exist in standard English. It’s always two words: a lot. Think of it like a little or a few—those are also two words, and so is a lot. On the SAT and ACT, answer choices with alot are always wrong.

A is correct. Affect is the verb here — “can seriously [verb] your performance.” Effect is typically a noun: “the effect of sleep deprivation.” A helpful check: try substituting influence (verb) or result (noun). This is one of the most frequently tested word pairs on the SAT.

B is correct. Rearrange: “I should address this letter to [who/whom].” Substitute: “I should address it to him” (not “to he”). Since him fits, use whom. The him/her → whom and he/she → who rule works every time.

B is correct. Lie = to recline (no object: you’re not placing anything). Lay needs an object: “Lay the book on the table.” The tricky part: past tense of lie is lay (“Yesterday she lay on the couch”). Past tense of lay is laid.

A is correct. Mistakes is countable (you can count: 1 mistake, 2 mistakes), so use fewer. Use less for things you can’t count individually: “less time,” “less water,” “less stress.” Grocery store “10 items or less” signs are technically wrong — it should be “10 items or fewer.”

A is correct. The tie doesn’t praise the suit — it goes well with it. That’s complement (to complete or enhance). A compliment is what you give someone when you say their outfit looks great. The SAT uses this pair to test whether students understand meaning, not just sound.

B is correct. Here the word means “main” (adjective), which is principal. Principle is always a noun: “a guiding principle,” “the principles of physics.” If you can swap the word with “main” or “primary,” it’s principal. If it’s a rule or belief, it’s principle.

B is correct. Except = excluding. Accept is a verb meaning to receive: “She was accepted to SMU.” Common error: students often write “I can’t accept for one problem” when they mean “I can’t do it except for one problem.”

A is correct. You’re not talking about physical distance here—you’re talking about the extent of a conversation. That’s figurative, so further is correct. Farther is for literal, measurable distance: “Dallas is farther from Austin than from Waco.”

B is correct in formal/test contexts. With five team members sharing a prize, use among. Use between for exactly two: “divided between Maya and Jordan.” On the SAT and ACT, the traditional rule applies: two items = between, three or more as a group = among.

A is correct. Ensure = make certain. Insure is only for financial insurance policies. Assure = “I assure you it will work” (always needs a person). SAT passage questions about word choice will test whether students know the precise meaning of each.

B is correct. Remove “Tyler and”: would you say “the coach gave I extra practice time”? No—you’d say “gave me.” Using “and I” sounds formal, so many people overuse it—but it’s only correct when “I” is the subject doing the action, not the object receiving it.

A is correct. “Could of” is a misspelling caused by the way could’ve sounds when spoken fast. “Could’ve” is short for “could have,” not “could of.” “Of” is a preposition—it can’t follow a modal verb like could, should, or would. This error will always be marked wrong on the SAT and ACT.

B is correct. Regardless already means “without regard.” Adding “ir-” creates a double negative that means the opposite of what’s intended. Both the SAT and ACT will always mark irregardless as incorrect. It appears in some dictionaries as “nonstandard”—on a standardized test, nonstandard is the same as wrong.

A is correct. In A, literally is used accurately: the screen actually displayed those exact words. In B, no one is actually dying—it’s hyperbole. On the SAT, a passage might ask you to identify the precise meaning of a word. If literally is used where figuratively is meant, that’s an error. In strong essay writing, avoid using literally as an intensifier entirely.