Plurals are usually formed by adding 's' or 'es'. I have two dogs. Their team has had two wins and two losses. An apostrophe is used for possessives: That is Robert's house. If the noun is plural and possessive, the apostrophe goes after the 's'. The boys' clothes are in the closet. Apostrophes are also used in contractions to show where letters were left out: It's sunny today (it is). He's my brother (he is). She's been sick since Sunday (she has).

"s" is plural. 's is for is, has and possession.

Ohh, Interesting...

sometimes people ( such as myself) are too lazy to put the apostrophe and so write : its instead of it's or dont instead of don't , that is why you see it witten that way, however writing that way is incorrect and you should follow Susan's rules below.

I know that is for a possesion, but many times i have seen that some people writes "For the" or "of the" and doesn't use the apostrophe