What is the adverb in sentence You should not fold any pages a library book?

The adverb in the sentence "You should not fold any pages in a library book" is not.

Here's why:

* Adverbs modify verbs, adjectives, or other adverbs. They tell us how, when, where, or to what extent something happens.

* In this sentence, "not" modifies the verb "fold," indicating that the action of folding should not occur.