s' or s's in possesive forms?

[tbentsen77]

As I have come to understand, today it's equally legal to use the s' and s's solution when dealing with possesive forms.

For example: Chris' dog / Chris's dog.

But what about the situations where we are not dealing with a name? In this case, I would definetely go with the s' option - but is the other one gramatically incorrect?

For example: The two boys' mother / The two boys's mother
All the girls' dolls / All the girls's dolls

Please don't misunderstand me, but I'd very much appreciate anwers based on solid grammatical rules rather than "I prefer"-argumetations.

Thank you in advance.

Kind regards
Tbentsen

[SoothingDave]

The rule you were given was for names that end in "s."

Plural forms of words, like "boys" form the possessive by adding an apostrophe. "Boys' toys" not "boys's toys."

[mykwyner]

The rule is that plurals of regular common nouns that are formed with an s become possessives with only an apostrophe.

The boy's mother was home. (one boy, one mother)

The boys' mother was home. (more than one boy, one mother)

When you are making possessives out of common nouns that end in s in the singular, the rule is the same.

The pants' zipper is broken. standard
The pants's zipper is broken. non-standard (We don't say "pants-ez zipper")