So, I'm going to talk to you about subject and verb agreement, particularly when you're dealing with one subject that is plural and one subject that is singular in the same sentence. It's really important that the subjects and the verbs in your sentences agree in terms of plurality. As a colleague of mine at Gotham Writers likes to say, "When your subjects and your verbs don't agree, you have to send them to couples' therapy." So in my grammar class, we send a lot of sentences to couples' therapy. They laugh, they cry, they smoke a cigarette, and they come back much better sentences.
So to make sure that your subject and your verb agree when you're dealing with two subjects in the same sentence and one is singular and one is plural, here's what you do. I'm going to give you an example of a sentence that has two subjects: one is plural, and the one is singular. In this case, the sentence is, "The boys and Jill run to the movie theater." So one of our subjects is "the boys", and we also have "Jill". "The boys" are plural, "Jill" is singular, but together, they form a complete plural subject. So in this case, we need the plural form of the verb "run". And to get the plural form of the verb, we drop the "s".
So, as a general rule of thumb, whenever you have a sentence with more than one subject or actor--in this case, we have "Jill" plus "the boys"--the subject is plural, and therefore, we need the plural verb.