Feedback for subjective question

Question 1: Pick out the main clause verbs and underline the subjects in the following sentences.

1. Pamela(Subject) sang a song(Main Cluse) at her sister's wedding.
2. Before visiting the library, Stephen did considerable research on-line.
3. California(Suject) continues(Main Clause) to lead the nation in population growth
4. Once a center of activity, the theater has fallen*(Verb) into disrepair
5. Griffin(Subject()'s soccer ball rolled into the street.(All is main clause)