Commonly Confused Words (Set 2)

Pairs that trip up native speakers too

These eight pairs cause errors at every level — including in published news articles and corporate emails. The good news: each pair has a clear rule, and once you internalise the rule, you’ll never confuse them again.

Pair	Quick test
affect / effect	Verb (to influence) vs noun (a result)
fewer / less	Countable vs uncountable
who / whom	Subject vs object
lay / lie	Transitive (needs object) vs intransitive (no object)
lend / borrow	Give → / Take ←
bring / take	Toward speaker vs away from speaker
principal / principle	Main person/thing vs rule/belief
complement / compliment	Completes vs praises

We’ll work through each pair with a definition, contrastive examples, and a memory trick.

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affect vs effect

This is the #1 most-confused pair in English. The rule is simple: affect is a verb; effect is a noun.

affect (verb): to influence, to change

The new law will **affect** small businesses.

Her mood **affected** the whole team.

Smoking **affects** your lungs.

effect (noun): the result of an influence

The new law will have a major **effect** on small businesses.

The medication had no **effect**.

We're studying the **effects** of climate change.

Memory trick: Affect = Action (verb). Effect = End result (noun).

The two rare exceptions

There are two cases where the parts of speech flip — both common in formal/academic writing:

1. effect as a verb = to bring about, to cause something to happen. The new manager **effected** several changes in the department. (= caused them to happen)

2. affect as a noun = an emotional state (used mainly in psychology). The patient showed flat **affect**. (technical term for visible emotion)

In everyday B2 English, you’ll almost always want affect (verb) + effect (noun).

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fewer vs less

The rule: fewer for countable nouns; less for uncountable nouns.

Countable → fewer

Things you can count individually have plural forms (apples, chairs, mistakes, people).

There are **fewer** students in the class today.

I made **fewer** mistakes than last time.

We need **fewer** plastic bags.

Uncountable → less

Things you measure rather than count (water, money, time, traffic, information).

I drink **less** coffee in the evening.

She has **less** patience these days.

There's **less** traffic on Sundays.

The famous supermarket sign

In many UK supermarkets you’ll see the sign “10 items or less”. Strict grammarians prefer “10 items or fewer” because items are countable. Both are now widely accepted in everyday writing, but in formal writing, stick with fewer for countables.

fewer than and less than with numbers

Numbers + units of measurement are an interesting case. When the number describes a single quantity (distance, time, money, weight), use less than even though numbers feel countable:

The journey takes **less than** two hours. (a single span of time)

She earns **less than** £30,000. (a single amount of money)

The package weighs **less than** five kilos. (a single weight)

But when you’re counting the items themselves, use fewer:

**Fewer than** ten people came. (counting people)

We have **fewer than** five tickets left. (counting tickets)

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who vs whom

The rule: who is a subject; whom is an object. (Whom is becoming rarer in casual speech, but it’s still standard in formal writing.)

who = subject (does the action)

**Who** called you? (who is doing the calling)

I know the man **who** lives next door. (who is doing the living)

The candidate **who** wins will start in May. (who is doing the winning)

whom = object (receives the action)

**Whom** did you call? (you called whom — whom is the object of “called”)

The man **whom** I met yesterday is a doctor. (I met whom)

To **whom** should I address this letter? (object of preposition “to”)

The substitution test

Replace the word with he/him (or she/her) and see which fits:

• He fits → use who.
• Him fits → use whom.

(Who/Whom) called you? → He called you → who.

(Who/Whom) did you call? → I called him → whom.

The man (who/whom) I met → I met him → whom.

The man (who/whom) lives next door → He lives next door → who.

Memory trick: Both him and whom end in m. If him works, so does whom.

Modern usage

In speech, who often replaces whom: Who did you call? sounds natural. In formal writing — emails to clients, essays, reports — whom is still expected after a preposition (to whom, with whom, for whom) and as the object of a verb in defining contexts.

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lay vs lie

This is the trickiest pair. The rule turns on whether the verb takes an object or not.

Verb	Meaning	Takes an object?	Forms (base / past / past participle)
lay	put something down	yes (transitive)	lay / laid / laid
lie	recline, rest	no (intransitive)	lie / lay / lain
lie (different verb!)	tell an untruth	no	lie / lied / lied

lay — you lay something down

Please **lay** the books on the table. (What do you lay? The books.)

She **laid** the baby in the cot.

The hen has **laid** an egg.

I **laid** the report on his desk this morning.

lie — you yourself lie down

I'm tired — I'm going to **lie** down. (No object after the verb.)

The dog **lies** by the fire every evening.

Yesterday I **lay** on the sofa for hours. (past tense of lie)

She has **lain** in bed all morning. (past participle)

Why everyone gets it wrong

The past tense of lie (recline) is lay — the same word as the present tense of the other verb. So “I lay on the sofa yesterday” is correct, but it sounds like the transitive verb. Most native speakers say “I laid on the sofa” — which is technically wrong.

Memory trick: Lay = Lay something. If there’s no object, use lie.

Quick test

Does the sentence have a direct object after the verb?

• Yes → lay / laid / laid
• No → lie / lay / lain

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lend vs borrow

Both verbs describe a temporary transfer, but the direction is opposite.

Verb	Direction	Memory
lend	give to someone	I lend to you
borrow	take from someone	I borrow from you

lend — give temporarily

Could you **lend** me your pen? (= give it to me temporarily)

The bank **lent** her £10,000.

I'll **lend** you my car for the weekend.

Past tense: lent (irregular).

borrow — take temporarily

Could I **borrow** your pen? (= take it from you temporarily)

She **borrowed** £10,000 from the bank.

May I **borrow** your car for the weekend?

Past tense: borrowed (regular).

The mirror

Every “lending” is also a “borrowing” from the other side. Think of one transaction with two viewpoints:

• I lend my book to Anna. (from my perspective)
• Anna borrows my book from me. (from her perspective)

Both describe the same event, but the verbs aren’t interchangeable — they describe different sides of the action.

Memory trick: YOU lend, and OU look like outgoing arrows. Borrow starts with a closed letter — the thing comes Back.

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bring vs take

Both describe carrying something, but the direction depends on the speaker’s location.

Verb	Direction	Pattern
bring	toward the speaker / listener	here ← there
take	away from the speaker	here → there

bring — to here

Can you **bring** me a glass of water? (toward me)

She **brought** her sister to the party. (the party is where I am)

Don't forget to **bring** your passport. (to the place we’ll meet)

take — to there

I'll **take** these books to the library. (away from here)

Please **take** the dog for a walk.

Could you **take** this letter to the post office?

Speaker viewpoint

Imagine where the speaker is standing. If the object is moving toward that spot, use bring. If it’s moving away from that spot, use take.

Don't **bring** that smell into the house. (the speaker is in the house — the smell would come toward them)

She **took** the children to school. (away from the home/speaker)

Are you **bringing** your laptop tonight? (the speaker is at the place where it’ll arrive)

Past forms

Verb	Past simple	Past participle
bring	brought	brought
take	took	taken

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principal vs principle

These two words sound identical but are unrelated in meaning.

principal (adjective or noun) — main, most important

As adjective: most important, primary.

The **principal** reason for the failure was poor planning.

Our **principal** concern is safety.

As noun: the head of a school; or a sum of money on which interest is paid.

The school **principal** addressed the assembly. (US English; UK uses “headteacher”)

Pay back the **principal** before the interest.

principle (noun only) — a rule, belief, or law

Honesty is an important **principle**.

This violates the **principles** of fair play.

The machine works on the **principle** of magnetism.

Memory trick

The school principal is your pal (friend). The other word, principle, ends like rule — and a principle is a rule.

Sentence	Correct word
The ___ of the school met the parents.	principal (the head — your “pal”)
She has strong moral ___.	principles (rules, beliefs)
Pay off the ___, then worry about interest.	principal (the main amount of money)
In ___, I agree with you.	principle (a fundamental idea)

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complement vs compliment

Same pronunciation, different spelling, completely different meanings.

complement — completes or matches well

As verb: to go well with, to complete.

The wine **complements** the meal beautifully.

Her skills **complement** mine perfectly.

As noun: something that completes.

The dessert was the perfect **complement** to dinner.

compliment — words of praise

As verb: to praise.

She **complimented** me on my presentation.

He **complimented** her cooking.

As noun: a polite expression of admiration.

Thank you for the **compliment**!

I'd take that as a **compliment**.

Memory trick

Compliment has an i for “I like it!” — when you compliment someone, you’re saying you like something. Complement has an e for “complete” — it completes or matches.

Sentence	Correct word
The hat ___s her dress.	complements (matches it)
She paid me a lovely ___.	compliment (kind words)
These two flavours ___ each other.	complement (work well together)
Was that a ___ or an insult?	compliment (kind words)

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Common Mistakes

Mistake	Better	Why
The weather effects my mood.	The weather affects my mood.	Affect is the verb (to influence).
It will have a big affect on sales.	It will have a big effect on sales.	Effect is the noun (the result).
There were less people at the meeting.	There were fewer people at the meeting.	People is countable; use fewer.
Less than 100 students applied.	Fewer than 100 students applied.	When counting individual items, use fewer.
Who did you give it to?	To whom did you give it? (formal)	After a preposition in formal writing, use whom.
I'm going to lay down.	I'm going to lie down.	No object → use lie. Lay requires something to lay.
Can you borrow me your pen?	Can you lend me your pen?	The giver lends; the taker borrows.
Bring this letter to the post office. (when you’re not at the post office)	Take this letter to the post office.	Movement away from the speaker = take.
He's a man of strong principals.	He's a man of strong principles.	Beliefs and rules = principles. The school head = principal.
Thank you, that's a lovely complement.	Thank you, that's a lovely compliment.	Praise = compliment (with an i).

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Quick-Reference Cheat Sheet

Pair	Use this for…
affect (v) / effect (n)	influencing / the result
fewer / less	countable / uncountable
who / whom	subject (he/she fits) / object (him/her fits)
lay / lie	put something down (object) / recline (no object)
lend / borrow	give temporarily / take temporarily
bring / take	toward speaker / away from speaker
principal / principle	main person or amount / rule or belief
complement / compliment	completes or matches / praises

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Practice: Exercises

1 / 15

Choose the correct word: 'How will the new law ___ small businesses?'

AeffectBaffectCeffectedDaffecting

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Summary

These eight pairs trip up writers at every level, but each has a clear rule:

• affect / effect — verb / noun. The law affects sales. The effect was small.
• fewer / less — countable / uncountable. Fewer people, less water.
• who / whom — subject / object. If him works, so does whom.
• lay / lie — needs an object / no object. Lay the book down. Lie down.
• lend / borrow — give to / take from. I lend it to you; you borrow it from me.
• bring / take — toward speaker / away from speaker. Bring it here; take it there.
• principal / principle — main person/amount / rule or belief. The principal is your pal; a principle is a rule.
• complement / compliment — completes / praises. The wine complements dinner; she paid me a compliment.

The two verbs (affect, lay/lie) and the two same-sounding pairs (principal/principle, complement/compliment) account for most published errors. Master these and your writing immediately sounds more polished.