How many verb endings are there?
The simple tenses (past, present, and future) are the most basic forms, but there are 12 major verb tenses in English in all.
Can you have 4 verbs in a sentence?
Theoretically, it is possible to have an infinite numbers of verbs in a single sentence. In actual usage, even simple sentences frequently contain more than one "main verb" in what is called a compound predicate.