Yes, that's one of the verbs. What are the others?
had
Yes -- "had" is a helping verb. What is the main verb?
fallen
Yay! You've got it.
The subject is rocks and the verbs are had fallen and shattered.
FALLEN
To find the verb in a sentence, we need to identify the word or words that express an action or state of being. In this sentence, the action word is "shattered." It describes what happened to the rocks after they fell onto the highway. The verb indicates the action that took place in the sentence.