Grandparents'
what does it mean with the apostrophe

Essentially, if the apostrophe is after the s, rather than before, it means that the sentence is referring to more than one grandparent, and their possession of more than one thing. Say your grandparents owned goats. You would refer to that as your "grandparents' goats" whereas, if they owned just one cow, it would be your "grandparent's cow." Hope this helps!

postive, comparative, superlative - good, better, best

recall how we defined nouns as words capable of having plurals and possessive endings. adjectives (and their first cousin, the adverb) also have a feature that distinguishes them. they come in three states. first, the raw adjective—in its positive state—merely describes the noun modified; it doesn’t care about how this particular person or thing stacks up against other members of the same noun class

marriage difficulties adversely affect parent-child communication