Common Grammar Mistakes Part Two: The Apostrophe

I see it with alarming frequency: misuse of apostrophes. It appears in the writings of my co-workers, on signs in front of businesses, even in newspaper and magazine articles. It's rampant in online discussion forums, which can be really distracting! Here's a little primer to help you decide when (or when not) to use an apostrophe.

Apostrophes are used for three basic reasons: to indicate possessive, to replace missing letters or numbers, and to show plurals of lower case letters only.

Possessive

The possessive form of a noun is used to show ownership, such as "Mike's car" or "the girl's bicycle." However, this is not used when clarifying or describing an object, such as "bicycle tire." The tire doesn't really belong to the tire in this sense; it's a part of the bicycle. However, if you were to say, "That bicycle's tire is flat," you are referring to a particular part of that particular bicycle and you would use the possessive form. Time can also be possessive: "Three hours' wait" refers to the wait of three hours. However the word 'hours' in "I waited for three hours" is plural, not possessive.

Now that you know when to use the possessive form, you need to know how to use the apostrophe correctly! Basically, if the noun is singular, such as "Shelly" or "man," put an apostrophe and then the 's.' This includes singular nouns that end in 's.'

•Shelly's sweater is pretty.
•The man's hat blew away.
•James's cat needs to go outside.

When showing the possessive of a plural noun, you have two options: if the plural noun does not end in 's,' add an apostrophe, then the 's.' if the plural noun does end in 's,' add the apostrophe after the existing 's' and do not add another one.

•The women's restroom is closed.
•The dogs' houses need to be cleaned.

Some words are already possessive and do not require an apostrophe, such as "his," "her," and "its." A common error is to use an apostrophe in the possessive form of "its," but this is not correct. "Its" is the possessive form of "it," just like "his" is the possessive form of "he." "It's" is a contraction for "it is."