10 Grammar Rules Every Teacher Should Know

Students’ parents are welcome to attend.
Whose parents are welcome to attend? The students’ parents are.


Onions in the sun smell strongest.
“In” doesn’t belong to anyone, so “onions” isn’t possessive.


Walla Wallas are the country’s favorite onion.
Whose favorite onion are Walla Wallas? The country’s.

Having said all that, let me explain the one exception to the apostrophe rules: the word “it.” Someone somewhere decided that “it’s” couldn’t represent both “it is” and possessive it. So he or she decided that “its” would be the possessive form. Instead of clearing up confusion, this exception causes it. These days it’s rare to see “its” or “it’s” used correctly. Here’s the right way:

Look, it’s a black labrador retriever! (it is a black lab)

I think its name is Barney. (the name of it is Barney)


Short Cut
To check your its/it’s form, replace it with “it is.” If the sentence makes sense, write “it’s.” If the sentence doesn’t, write “its.” Also, “its” answers the question “whose is it?” above.