The following is a list of homonyms (words that sound alike) that writers mix up on a regular basis. It’s a good idea to train your eye to catch these errors because programs like Spell Check won’t always flag them.
ARE VS. OUR
“Are” is a linking verb, while “our” shows possession.
Those teams are not as competitive as our group of athletes.
COMPLIMENT VS. COMPLEMENT
You give someone a “compliment.”
Your hair looks nice today. … I like your new boots.
Use “complement” when you want to show that two things go well together.
Peanut butter complements jelly.
EFFECT VS. AFFECT
“Effect” is most commonly used as a noun meaning “result” or “outcome.”
The effects of my midterm grade were devastating.
“Affect” is usually used as a verb (think “A” for action) meaning “to influence.”
My midterm grade negatively affected by GPA.
Side note: Affect can also be used as a noun in psychology.
This is a helpful LINK if you have any second guesses about whether to use "effect" or "affect."
EXCEPT VS. ACCEPT
“Except” implies exclusion, whereas “accept” means to take or receive something.
I won’t accept use of your Visa except in cases of emergency.
INSURE VS. ENSURE
“Insure” relates to insurance (what you rely on when you crash your car or when your apartment floods), while “ensure” just means to make sure that something happens.
I ensured my mother I had renters insurance before I moved into my new apartment.
ITS VS. IT’S
To avoid confusing these two words, you just have to commit them to memory.
“Its” implies possession.
“It’s” is a contraction of “it is.” The apostrophe in a contraction is a visual cue that a word was left out. The apostrophe in “it’s” visually highlights that the word “is” has been removed for the sake of brevity.
It’s a beautiful neighborhood. Every street has its own unique look.
“Their” shows possession, while “there” is a place, and “they’re” is a contraction of “they are.”
They’re heading over to their house, which is over there.
THEN VS. THAN
“Then” denotes a time frame or a sequence of events.
She went to the store, and then she went to the bank.
“Than” is used to compare things or situations.
I am more tired than you are.
WHICH VS. THAT
Use “that” if the words that follow are essential to the meaning of the sentence.
If removing the words that follow “that” or “which” does not change the precise meaning of the sentence, then you can use “which.” Remember, “which” is almost always preceded by a comma because it is part of a non-restrictive clause (removing it wouldn’t change the precise meaning of the sentence) that just adds more information to the sentence.
Incorrect: One aspect of the class which affects my grade is class participation.
Correction: One aspect of the class that affects my grade is class participation. (“Affects my grade” is essential to the precise meaning of this sentence; therefore, use “that.”)
Here’s a helpful LINK on the topic.
YOUR VS. YOU’RE
“Your” implies possession, while “you’re” is a contraction of “you are.”
I am going to steal your sandwich from the fridge.
You’re going to pay me back for my bread, meat, and cheese.