I know that one can use "they" / "them" / "their" in place of "he" / "him" / "his" or "she" / "her" / "hers" when the subject's / direct object's gender is not known; for instance, just looking at the default user's about me section on Stack Exchange sites:
Apparently, this user prefers to keep an air of mystery about them
My question is what happens when someone wants to reference the subject using a pronoun instead.
Should the verb be conjugated accordingly to the pronoun? E.g.:
Apparently, they prefer to keep an air of mystery about them
Or should the conjugation be retained? E.g.:
Apparently, they prefers to keep an air of mystery about them
The former looks unclear because it wouldn't allow the reader / listener to understand if the writer / speaker is talking about a single person or about a group of people, however the latter sounds very weird, at least just to the non-native speaker which I am.