www.englishclub.com › Learn English › Grammar › Nouns
Possessive ‘s. When we want to show that something belongs to somebody or something, we usually add ‘s to a singular noun and an apostrophe ‘ to a plural ...
Please don't take this as being argumentative but I think you might be wrong!!!
Sorry, but personal possessive pronouns (ours, yours, theirs, its) do NOT get apostrophes for any reason. I teach English, but not in the public screwels.