How does subject-verb agreement work with a compound subject?
Subject-verb agreement for compound subjects can seem complex, but there are two basic rules to keep in mind.
For compound subjects connected with “and,” a plural verb is almost always used (e.g., “Carlos and Elise go to the same school”).
For compound subjects connected with “or” or “nor,” the verb agrees with whichever noun is closest to it (e.g., “Either my parents or my sister picks me up from school” or “Either my sister or my parents pick me up from school”).