Final answer:
Compound subjects joined by 'or' or 'nor' may take a singular or plural verb depending on the sentence structure and the subject closest to the verb in form.
Step-by-step explanation:
Depending on the sentence structure, compound subjects joined by or or nor may take a singular or plural verb. If the subjects are joined by or, the verb agrees with the subject closer to it. For example, 'My sister or my brother is coming.
However, if the subjects are joined by nor, the verb agrees with the subject that is closer to it in form. For example, 'Neither the cats nor the dog are going outside.'
So, the verb used with compound subjects joined by or or nor depends on the sentence structure and the subject closest to the verb.
Learn more about Subject-Verb Agreement