Verb refers to the action words such as to sing, to dance, to eat and so on. The verbs act as a link between the subject and the information provided about the subject. Whereas, the verb phrase that contains either an indirect and direct object or both the verb. The verb phrase can also act as an adjective or adverb and contain a verb. A phrase can act as a predicate of a sentence or clause.
Therefore, in the above sentence, verb phrase is should have been. Herein, 'Should' and 'have' are the auxiliary verbs and 'been' being the main verb.
