This a tutorial study based on grammar rule. Here briefly focus on Subject-Verb Agreement. Subjects and verbs must “Agree” with one another in number (singular or plural). Thus, if a subject is singular, its verb must also be singular; if a subject is a plural, its verb must also be plural. In the present tense, nouns and verbs form plurals in opposite ways: nouns ADD an s to the singular form; verbs REMOVE the s from the singular form.