21c. Subjects joined with and
21cTreat most subjects joined with and as plural.
A subject with two or more parts is said to be compound. If the parts are connected with and, the subject is nearly always plural.
exceptions: 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.
Fish and chips was a last-minute addition to the menu.
Sue’s friend and adviser was surprised by her decision.
When a compound subject is preceded by each or every, treat it as singular.
Each tree, shrub, and vine needs to be sprayed.
Every car, truck, and van is required to pass inspection.
This exception does not apply when a compound subject is followed by each: Alan and Marcia each have different ideas.