When you learn English, you have to understand that English grammar is not that difficult compared to other languages, but you have to pay attention to the rules and the exceptions to the rules. One of the many mistakes I have noticed is the wrong use of different "s"-es that have different grammatical functions. Of course, these mistakes can only be seen in written.
- One common mistake is the "s" after a family name to refer to the whole family, for example The Browns, The Jonsons and NOT The Bronw's, The Jonsons's.
- Then we have the possessive " 's "
- when we have one owner we use " 's " as in the girl's doll, the boy's ball.
- when we have several owners we use just " ' " as in the girls' doll, the boys' ball. for plurals that do not end in " s ", we use " 's " as in the children's toys, the women's hats.
- The ending " s " for the third person singular of the present simple - he eats, she runs. When in the negative we only have the "es" in "does" - he doesn't eat, she doesn't run. The 3rd person of the Present Simple is the only one that is marked by "s/es".