Grammar is definitely one of the biggest downfalls of NS. This is partly why the folks on TGR have such a low opinion of our site. Take a few seconds and refer to the guidelines below before posting.
They're, Their, and There
-They're is a contraction for they are. If you could say they are instead of they're, this is where they're should be used.
-Their refers to someone's thing. eg. This is their backpack. Here is their school. Should we go to their house?
-There- this refers to a place. I took my sister there. I once went there on a field trip.
Your and you're
-Your is possessive- Here is your backpack. No it's not mine, it's yours.
-You're is a contraction of "you are". You're stupid because you used your instead of you're.
Skis vs skies vs skiis vs ski's vs skii's
THERE IS ONLY ONE WAY TO SPELL SKIS AND ITS SKIS.
-skies is the plural of sky
-I don't know what skiis mor skii's are.
-ski's is never to be used
Using apostrophes properly
An apostrophe is used to denote the possession of a noun
-IE Sam's bike. Ernie's cabin.
-NOT I am eating "carrot's"
It's is a contraction of it is, conversely "Its" refers to the possessive ---The bird is in its cage.
It's don't not dont.
It's a lot not alot.
I have obviously not included everything, so feel free to add to the list, but make sure you're correct before posting.