In this sentence, the subject is mother. As the sentence concerns only one mother, the subject is singular. The verb in this sentence must be in the singular form of the third person. A composite subjectA subject that is formed when two or more names are connected by the coordination conjunctions and, or, or nor. is formed by two or more names and conjunctions of coordination and, or, or not yet. A composite subject can be composed of singular subjects, plural subjects, or a combination of singular and plural subjects. This only applies to present verbs (i.e. when the verb plot takes place in the present moment). Most other forms of time do not use the -s at all: she saw that he goes to see Caesar is used to seeing.* It is really very simple and should be automatic for most English speakers: I read, you read, but he reads.