In school, I was taught whenever coming across the pattern "either..or" or "neither..nor", we should always consider the noun/pronoun nearer to the verb when deciding which form to use.
Neither my parents nor John _______ (agree) with that.
In this case, we should use "agrees" instead of "agree" since John is closer to the verb.
Then I have a question. What if when there is only "either" or "neither"?
There are two particles: quarks and gluons. Neither ________ (detect) in the lab in isolated form yet.
In this case, should I use "has been detected" or "have been detected"?