Can you please explain some more about using the masculine or neuter plural adjective to designate a class of people or things? Specifically, when to use the masculine and when to use the neuter? From the text it looks like the masculine is used for people and the neuter is used for things. I think we are confused because "thing" (res) is feminine.
And about using adjectives as nouns: are they always in the masculine plural form?
I hope my questions are clear! Thank you!