by Annette Lyon
I know, I know. This one is so easy to confuse, which is why I'm writing about it. I've gotten this question a few times, so I thought I'd address it.
Daniel's coat and Megan's shoes need apostrophes to show ownership. As a result, we're used to adding the little curly mark to tell people that the car's tire is flat or the cat's litter needs to be changed.
So it's SO easy to let the little squiggly bugger sneak in where it's not welcomed and where it doesn't belong: in a possessive pronoun.
In English, we have two pronouns in particular that tend to get an apostrophe shoved into them incorrectly on a a regular basis. It's so common that many people don't even realize it's incorrect. After all, Mrs. Smith's class gets an apostrophe. So does Mom's car.
When I'm taking the dog to the vet, why don't I say mutt is getting it's shots?
Or when someone drops a dirty sock on the floor, why isn't it correct to ask who's it is?
Because possessive pronouns don't take an apostrophe. They are special: they're already possessive. Adding an apostrophe makes it redundant.
Actually, that's not entirely true. The apostrophe turns the word into a contraction, giving the sentence a meaning you didn't intend.
Taking the sentences above:
The mutt is getting it's shots.
When a word has an apostrophe, it's usually a contraction of two other words, like do and not creating don't, or can and not making can't.
In the same way, IT'S comes from IT and IS.
So what you are actually saying is: The mutt is getting it is shots.
The same thing applies to who's and whose.
Think of the apostrophe as a big, red flashing light that warns you:
This is a word that originally came from two words. It's NOT a pronoun.
Let's take the other commonly mistaken pronoun:
WHO'S is a contraction of WHO and IS.
Look at the sentence above, and you'll realize it doesn't make sense when you pull the contraction apart:
Who is sock is this?
Okay . . .
For me, an easy way to remember the rule is to focus on that apostrophe and imagine it elsewhere. Think of possible replacements. Could they fit? In other words, what other other possessive pronouns fit?
Note how none of them have an apostrophe. But hey, let's try adding one:
Um, no. That doesn't work. So ITS and WHOSE don't get the apostrophe either.
Not even when you're adding an S, such as, "Is this sweater yours?"
Still NO apostrophe. Same with OURS, THEIRS, HERS, etc.
Pronouns hate apostrophes. Say it to out loud. Say it again. And again, until it's ingrained in your mind.
Wash and repeat.