Commonly Confused Words
Pairs of words that are often mixed up, with the difference and an example for each.
These pairs cause many errors in writing. Learn the difference for each.
affect and effect
- Affect (usually a verb): to influence. The weather affected the match.
- Effect (usually a noun): a result. The effect of the weather was a delay.
- A quick test: if you can put "the" before the word, it is probably effect. (Both words have less common uses, such as "effect change", meaning to bring it about.)
their, there, they're
- Their: belonging to them. Their books are on the table.
- There: a place or the existence of something. The books are over there. There is a problem.
- They're: they are. They're late.
its and it's
- Its: belonging to it. The dog wagged its tail.
- It's: it is or it has. It's raining.
then and than
- Then: at that time, or next. We ate, then we left.
- Than: used in comparisons. She is taller than her brother.
your and you're
- Your: belonging to you.
- You're: you are.
principal and principle
- Principal: a main thing, or the head of a school. The principal reason...
- Principle: a rule or belief. It is a matter of principle.
accept and except
- Accept: to receive or agree. She accepted the offer.
- Except: excluding. Everyone except Tom arrived.
fewer and less
- Fewer is used with countable nouns: fewer apples.
- Less is used with uncountable nouns: less water.
Strategy for exams
Read your writing aloud in your head. Substitute the longer form ("it is", "they are") to test contractions. If it makes sense, use the contraction.