They'd redone their menus, and when I opened it, my eye immediately twitched at one heading...
Okay, here goes.
- Apostrophes are used to designate contractions (it's = it is, she's = she is) and sometimes possessive (that is Susie's dog, that is the Smiths' house).
- Apostrophes are NOT used to designate plurals, unless it's a plural possessive, UNLESS...
- ...it's the plural of a letter of number. (He received three A's on his report card.)
- To designate omitted letters in some words. (I saw him runnin' like a scalded cat.)
So when you don't know if you're supposed to use dogs or dog's, for example, SAY the sentence out loud, and expand the word. Use the one that's correct:
- It is the bowl of the dog. (dog's - correct)
- It is the "dog is/bowl of the dog" bowl. (using dogs - incorrect)
- There are five dogs. (dogs - correct)
- They have five dogs. It is the dogs' bowl. (dogs' - correct, because there are more than one dog, and the bowl belongs to the dogs, plural.)
It/it's gets people.
- It's hot. (It is hot. - correct)
- Its hot. (incorrect)
- It's five o'clock somewhere. (It is... - correct)
- Its clock is wrong. (Its - correct)
If you can say "it is" instead of "it's" and it is correct, then you use "it's."