Pause with me for a moment as we consider those pesky 'postrophes. The apostrophe should be your friend, not another headache, but he does have to do his work properly. And being a lesser used punctuation mark, he gets misused almost as often as his big sister the comma.

And now today's lesson:
1) The apostrophe can and should be used to show possession--as in the previous phrase ("today's lesson"). The lesson belongs to today. Just as you can refer to this webpage as Benjie's blog because it belongs to me. [The most notable exceptions to this rule come from the pronoun family in the form of the words "it" and "who" in which we find that when the dog owns a bone (and we don't know the dog's gender) we say that the item is "its bone"--no apostrophe. In the case of our little interrogative friend who, possession is shown by asking "Whose book is this?"--again, no apostrophe.]

2) One may also use the apostrophe when contracting words (creating contractions) such as can't or won't (can + not = cannot contracting to can't; will + not contracts to won't). This is the rule that applies to our pronouns from example one in conjunction with the apostrophe. It's is the contraction for it and is, just as who's is the contracted form for who and is.

Please do not use the apostrophe when forming plurals (notice I did not write plural's) because that would just be silly. The struggle you will have is when writing about decades using numerical designation instead of words. Let me help you: the decade of the Sixties (including 1961-1970, another lesson altogether) would be written as the 60s, not the 60's (you may include an apostrophe to indicate that you have left out the first two numbers if you want: '60s).

Please treat him nicely because, after all, the apostrophe is your friend.