Only the parents or Geoffrey is allowed to speak during their presentation.
(Notice the singuler noun “Geoffrey” requiring the singular verb “is.”)
Either pasta or beans need to be added to the soup.
(Notice the plural noun “beans” requiring the plural verb “need.”)
Either the couch or the side tables have to be moved.
(Notice the plural noun “tables” requiring the plural verb “have.”)
Neither storms nor snow is delaying tonight’s football game.
(Notice the singuler noun “snow” requiring the singular verb “is.”)