Jack, let me further explain my post above--
If you have more than one noun in the subject of a sentence, like this, "Dogs, cats, and hamsters make good pets for children", you will say--when speaking about grammatical structure: "The subject of the sentence is 'dogs, cats, and hamsters', and the verb is 'make'. You do not say, "The subjects of the sentence are 'dogs, cats, and hamsters', and the verb is 'make'."