I will be the first to admit that punctuation rules are rather dull. Learning them in elementary and middle school bored me tremendously. However, you gain a lot from knowing how to connect ideas and sentences properly; you will write better papers if you can punctuate well. So I've set out some quick guidelines for punctuation use.


Use apostrophes for contractions (such as don't and shouldn't) and for possessives. To indicate possession, add an apostrophe and an s to (1) singular nouns and (2) plural nouns that don't end in s. For example:

The cat's collar
Thomas's cat
The children's cat

Yes, that second one is right: Thomas is singular, and so it gets an apostrophe and an s. (Please note an exception to this rule: classical and Biblical names get just an apostrophe, as in Jesus' mother or Odysseus' trickery.)

For a plural noun that ends in s, just add an apostrophe, as in

The cats' collars
The kids' cat

People often treat singular nouns that end in s (from names like Thomas to words like boss) the same way as plural nouns, adding an apostrophe but no s. Do not do this, please. Every time you do, I die a little inside.


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