Subject-Verb Agreement

Subjects and verbs must “agree” in number (singular or plural) and person. The concept of agreement is particularly relevant to:

1) the present simple tense: subjects in 3 rd person singular (he, she, it) take verbs with the ending -s

2) the verb to be: it can take forms am/is/are and was/were

3) the verb to have: it can take forms have/has

Note: If a sentence contains a modal verb (e.g. should, can, could, must, may), this modal must be followed by the base form of the verb regardless of the subject’s number and person. For example: The witness must report to the police (not must reports).

Below are the rules for subject-verb agreement.

• Make sure the verb agrees with its subject, not with a word that comes between the subject and the verb (whether in preposition phrases or adjective clauses).For example: The samples on the tray in the lab need testing. (prepositional phrases)
  The governor, as well as his press secretary, was applauded. (an adjective clause) Note: A subject can never be a part of a prepositional phrase (e.g. in the lab is a prepositional phrase because it starts with the preposition in, so the noun lab cannot be a subject of a sentence).
• Make the verb agree with its subject even when the subject comes after the verb.

For example: Matt and Lisa often write in the morning.
Sonja’s ability and desire to help are inspiring.

However, when the parts of the subject form a single unit or when they refer to the same person or thing, treat the subject as singular. In addition, when a compound subject is preceded by each or every, treat the subject as singular.

Adapted from: A Writer’s Reference (7th ed.) by Diana Hacker.

Grammar & Style

• Converting Fragments to Full Sentences
• Active and Passive Voice
• Choosing Between Infinitive and Gerund: “To do” or “doing”?
• Choosing the Correct Word Form
• Combining Clauses to Avoid Comma Splices, Run-ons, and Fragments
• Commas, Semicolons, and Colons
• Count vs. Noncount Nouns
• Definite and Indefinite Articles
• Improving Cohesion: The "Known/New Contract"
• Modal Verbs
• Parallel Structure
• Prepositions
• Pronouns
• Proper Nouns
• Reducing Informality in Academic Writing
• Run-on Sentences
• Same Form, but Different Functions: Various Meanings of Verb+ing and Verb+ed
• Subject-Verb Agreement
• The Three Common Tenses Used in Academic Writing
• Using Reduced Relative Clauses to Write Concisely
• Verb Tenses
• Word Order in Statements with Embedded Questions