Title: Interrupting Words and Relative Pronouns as Subjects
Course: Introduction to Grammar

It's quite simply, really, until you get into interrupting words and relative pronouns as the subject.

Interrupting Words

A verb always agrees with its subject--whether the verb comes right next to the subject or is separated from it by other words.

The subjects in the following examples are in blue; the verbs are in red. Notice that they agree in number--despite the words that separate them.

Prepositional Phrase | The winds at the summit were howling. The plural verb were agrees with the plural subject winds, even though summit is closer to the verb.
Participial Phrase | The backpack filled with ropes was put on the table. Was agrees with the subject backpack --not with ropes.
Negative Statements | David, not one of his brothers, is going to climb. Is agrees with the subject David--not with brothers.
Adjective Clauses | Hikers who are climbing the mountain prepare for every emergency. Prepare agrees with the subject hikers--not with mountain.

Compound prepositions, such as in addition to, as well as, along with, and together with, often begin interrupting phrases. Make sure the verb always agrees with the subject, not with the ojbect of the compound preposition.

Shauna, in addition to her two cousins, is coming with us.

Relative Pronouns as Subjects

When a relative pronoun is the subject of a subordinate clause, the antecedent determines the number of the verb.

Dr. Francis is the only surgeon in the country who knows how to perform this operation. (who refers to only surgeon, which is singular, so the verb knows is singular)

Dr. Klein is one of a dozen doctors who make this hospital famous. (who refers to a dozen doctors, which is plural, so the verb make is plural)