Usage and Grammar
Q. Sometimes I have a hard time distinguishing between a predicate adjective and a past-tense verb being used in a passive-voice construction. For example, in “this dish was leftover,” is “leftover” an adjective, or should it be “was left over,” with “left” being a verb and “over” being an adverb?
A. That’s tricky because “leftover” is both a noun and an adjective. The noun, which is usually plural, would require an article in the singular: a leftover. So the dish was either a leftover (sing. noun) or it was left over (the phrasal verb from which the noun and adjective are derived). Either one will work. It might also be described as a dish of leftovers (pl. noun). But the adjective form really only works before the noun: this leftover dish.