Sarah said that she felt sorry for the students who weren't able to go on the field trip. which phrase or clause in this sentence acts as an adjective modifying the word "students"?

I think it would be “who weren’t able to go on the field trip”

Allusion and illusion. an allusion is an indirect reference, whereas an illusion is something that is unreal or incorrect. each of the nouns has a related verb form: allude “to refer indirectly to,” and illude (not a very common word), which may mean “to delude or deceive” or “to subject to an illusion.”