Which is correct: "your" or "you're" ?
It's very easy to get these two words confused! But there is an important difference in their meanings.
"your" means belonging to you.
"you're" is a contraction of "you are".
Correct: "Here are your instructions for today."
Incorrect: "Here are you're instructions for today."
Correct: "Surely you're not serious!"
Incorrect: "Surely your not serious!"
Find the answers to grammatical puzzles like this in The Grammar Cookbook!