your and you're . . .

where do I begin? This one just really bugs me. Maybe it's because I had to teach contractions in first grade and if first graders are starting to get it, then I'm pretty sure this one should be common sense for adults. SO here we go:

your shows posession as in
That is your dog.
The dog belongs to the person, so the spelling y-o-u-r should be used here.

you're is a contraction, meaning you are as in
I'm sad that you're sick.
You could just as easily say I'm sad that you are sick.

The easiest way to remember which form of your to use is to try saying your sentence saying "you are" instead of "your." If it works, then you need to use you're, if it doesn't then you need to use your.

Example:

If your sentence is "I'm sure you're going to do great." Then you should say, "I'm sure you are going to do great." That sentence still makes sense, so the contraction is the right form of your to use.

Tomorrow's lesson will be on there, their, and they're.

*Disclaimer: I'm not so great at all other grammer, so don't judge me. And I start sentences with conjunctions, and I overuse commas, and I always use runon sentences. Sorry.