In English, all verbs have affirmative sentences and negative sentences. In the simple present tense, the affirmative form of verbs is the basic form, that is, the first person singular "am", the second person singular "are" and the third person singular "is". The negative form is realized by adding "not" before the verb. For the verb "are", the negative form is to add "not" before it, that is, "are not".