APART from extraposition, or deferring the subject to the tail end of a clause or sentence, there's still another sentence ...

A phrase is a group of two or more words that does not contain a subject and a verb working together. There are many types of phrases, including verb phrases, adverb phrases, and adjective phrases.

The subject (agent) is often dropped in passive sentences. The subject has become the object of the prepositional phrase, “by the student.” Accordingly, the subject can often be cut from passive ...