Via this column, we'll explore one grammar rule each week. If you have a grammar question you'd like me to address, please drop me a line at grace.lavigne@prnewswire.com and I'll do my best to answer it.

You no longer need to hide from apostrophes! Today we're reviewing the rules of apostrophes using spooky examples to chase away this grammar nightmare -- just in time for Halloween!

We use apostrophes for two main reasons:

1. To signify the exclusion of a letter in a contraction:

• I'm/I am going to dress up as Carmen Sandiego for Halloween.
• You can't/cannot dress up Freddie! (or I'll have nightmares…)
• You're/You are going to be Indiana Jones instead.

2. We also use apostrophes to show possession (which is to own something) of singular and plural nouns:

• If a word is simply plural, don't use an apostrophe:
  • I saw two kids fighting over candy corn.
  • How many chocolates have you eaten? (Too many.)
• But there are two exceptions:
  • If the word is a single letter:
    • How many e's are in "eerie"?
    • There are three m's in "mummy."
  • If a decade is abbreviated:
    • In the '90s, zombies took over the world.
    • Harry Houdini was born in the 1870s. (no apostrophe)

• To indicate possession, use an apostrophe:
  • The werewolf's face is repulsive.
  • The witch's cauldron is bubbling.
• But if the word is plural and possessive, put the apostrophe after the "s":
  • The werewolves' faces are repulsive.
  • The witches' cauldron is bubbling.
• Unless the word is already plural:
  • The children's faces were filled with fear.
  • The people's screams were bloodcurdling.

• If a name is possessive (and singular or plural) and ends in "s," drop the second "s":
  • Charles' gravestone is cracked.
  • The Mansons' plan was evil.

• Never use an apostrophe for pronouns, since they already indicate possession:
  • The mask is your's (wrong).
  • The cape is hers. (right)

Common Confusion:

• "its" vs. "it's"
  • Are you trying to say "it is" or "it has"? Use an apostrophe:
    • It's that black cat again.
    • It's been in the cemetery for a long time.
  • Are you indicating possession? No apostrophe:
    • The bat is known for its distinctive ears.
    • The skeleton lost its head.
  • If you're not sure, try replacing "it's" or "its" with "it is" (or "it has"). If it sounds OK, use an apostrophe:
    • The clown has its shoes off.
    • The clown has it is shoes off. (wrong, no apostrophe)
    • It's that creepy clown with no shoes again.
    • It is that creepy clown with no shoes again. (right, use apostrophe)
• The same rules apply for "whose" vs. "who's"
  • Possession
    • Whose wand is that?
    • A ghost whose time has come.
  • Contraction
    • Who's carving a pumpkin?
    • Who's seen his fangs?
  • If you're not sure, try replacing it with "who is" (or "who has"). If it sounds OK, use an apostrophe:
    • A wizard whose mind is evil.
    • A wizard who is mind is evil. (wrong, no apostrophe)
    • The wizard who's evil.
    • The wizard who is evil. (right, use apostrophe)