Delahunty and Garvey
agreement pattern we must change the past tense verb to the present tense.
Then we can systematically change the NPs in the sentence and observe
whether we must also change the verb. When we find the one (and there will
be only one) NP that forces us to change the verb in order to create a gram-
matical sentence, we will have found the subject of the sentence. Consider:
(13) a. I liked your poem.Change (13a) to present tense:
(13) b. I like your poem.Remember that only a third person singular subject requires the -s ending
on the verb. Note that your poem is third person. If your poem were the sub-
ject, the verb would be likes. Therefore your poem is not the subject. I is not
third person singular, but if we change it to She we have to change the verb
to likes to maintain grammaticality.
(13) c. She likes your poem.We can conclude that She is the subject of (13c), and because She replaced I in
(13b), I must be the subject of (13b) and also of (13a).
Exercise
Using only subject-verb agreement (that is, change the NPs and ob-
serve whether the verb form must also change), identify the whole
subject in each of the following sentences.
a. He eats a bagel every morning.
b. She sees her dentist at least twice a year.
c. Gasoline costs a fortune these days.
d. He sent his mother flowers for Mother’s Day.
e. Chickens cross roads.
f. There are several cookies in the box.
g. It is raining.
What problems did you encounter? How did you solve them?
Another way to determine the subject of a sentence is to replace all its NPs
with pronouns. The NP that can only be replaced by a pronoun in the nomi-