The key to understanding the difference lies in recognizing the distinct roles
the two subjects have in these sentences. In sentence 34, the subject is an agent
performing an action. In sentence 35, the subject is not an agent, so it does not
perform an action, which means thatthrobbingcannot describe an action in this
case because no action is performed. Instead,throbbingprovides existential in-
formation. On this account, we can say that progressive forms always have an
agentive subject. Whenever the subject is not an agent, the verb phrase consists
of a linking verb and predicate adjective. This analysis is supported by the
structures of sentences like the following:
- Mrs. DiMarco was boring.
- Mrs. DiMarco was boring Raul.
In the first example, Mrs. DiMarco is not an agentive subject, whereas in the
second she is. The difference in function not only results in different grammati-
cal analyses but also, as we should expect, in different meanings. Further sup-
port comes from the fact that words likethrobbingalso can function as simple
adjectives, as inShe had a throbbing headache.Following are some additional
examples for illustration:
- Macarenawas joggingalong the beach. (progressive verb form)
132 CHAPTER 4
Sentence 4.35: His toe was throbbing.