A subject is a person or thing performing an action or being described. Keep in mind the subject will always be a noun or pronoun. In the sentence, “I went running,” I (a pronoun) is the subject; the verb being performed is running.
A subject complement is a noun, pronoun, or adjective that follows a linking verb. Become, seem, and any form of the verb “be” are all true linking verb; that is, they will always be linking verbs. Verbs such as feel, look, and grow can be linking or action verbs. Ask yourself it this is something the person or thing (the subject) can do. If the answer is yes, you have an action verb. You can also substitute the verb in question with am, is, or are. If the sentence makes logical sense, you’re dealing with a linking verb. If the sentence doesn’t make logical sense, you’re dealing with an action verb.
That said, knowing the function of the verb is a guaranteed way of knowing what kind of verb you have. With the word “appear” for example, the substitution does not work and is an action that can be done.
Look at the following sentence: “The transcript appeared on my desk just hours after the deposition ended.” In this instance, “appeared” is describing where the transcript is physically at after the deposition. Remember, linking verbs do not express action, so something physically happening to the transcript rules out “appeared” being a linking verb here. Linking verbs also connect the subject of the verb to additional information about the subject. If there are more than one subject and verb in a sentence, focus only on the subject and verb pair that go together.
“The transcript appeared to be littered with technical medical jargon.” Here, “appeared” is linking the subject, the transcript, to what kind of information is in it, which is medical. No physical action is being talked about, even if the act of reading the transcript is physically doing something. Keep in mind that when punctuating a sentence, you can only go based off what is written.
The next topic will be about direct objects, indirect objects, and objects of preposition.