Which of the following statements is a fact?

a: whales are really cool.
b: whales are among the largest animals in the world.
c: all whales will be extinct in five years.
d: whales are fascinating creatures.

the answer is:

when will (v) the books (n) be (v) due?

nouns refer to people (other than pronouns), places and things, whereas verbs describe actions and are usually part of the predicate of a sentence. finally, pronouns can work as nouns and identify the participants in speech.

in the example sentence, "will" is a verb part or auxiliary verb, "be" is an infinitive verb and "books" is a plural noun.