Apostrophe.me is a simple how to use an apostrophe website that provides a quick online “how to” flowchart for using the apostrophe sign. It asks basic questions like “Is it plural?” or “Is it indicating possession? and gives example situations when you would use an apostrophe.
The site is very useful for people who are not native English speakers.
Oh and Who’s/Whose goes as such:
– “Who is” the only possessive pronoun not to use an apostrophe! “Who’s” is a contraction of “Who is” as in “Who is that?” – “Who’s that?” versus “Whose“, the possessive pronoun “Whose car is that?”
Check out Apostrophe.me @ http://theoatmeal.com/comics/apostrophe