Grammar Tip

When you're writing an invitation, is it "your invited" or "you're invited"? A quick memory trick to try is to think about the word. Is it two words or one?

Two words, put in an apostrophe and an "re." You are becomes you're. (You're invited to a party.)
One word, don't use the apsotrophe. (The party is at your house.)

I was reading a professional manual today and this grammar error was in their book. Many people make this mistake. But just remember to think--one word or two?