Is became a linking verb of be?

Yes, "became" is a past tense form of the linking verb "to be". It's used to connect a subject with a predicate nominative or predicate adjective, describing the subject's state or identity.

Here are some examples:

* She became a doctor. (The subject "she" is linked to the predicate nominative "a doctor")

* The sky became dark and stormy. (The subject "sky" is linked to the predicate adjectives "dark" and "stormy")

Let me know if you have any other questions about linking verbs!