Plural nouns take plural verbs and singular nouns take singular verbs, even if a phrase ending in a plural noun follows a singular subject or if a phrase ending in a singular noun follows a plural subject.
A review of all patients with grade 3 tumors was undertaken in the university hospital. [The subject in this sentence is review. Ignore all modifying prepositional phrases that follow a noun when determining verb agreement.]
The patient, one of many study participants given access to state-of-the-art medical care from the university’s clinical researchers, were followed up for more than a year. [The verb should be was followed up—the subject is patient.]
Sometimes the simplest solution is to rewrite it as 2 separate sentences:
The patient was followed up for more than a year. She was one of many study participants given access to state-of-the-art medical care from the university’s clinical researchers.
If the intervening phrase is introduced by with, together with, as well as, along with, in addition to, or similar constructions, the singular verb is preferred if the subject is singular because the intervening phrase does not affect the singularity of the subject.
The editor, as well as the reviewers, believes that this article is ready for acceptance.
The investigator, in addition to all participants, was expected to abide by the institution’s safety guidelines.
In these instances, recasting the sentence may eliminate confusion.
The patient, physician, and family members make this decision together.