If the verb is the simple present or past tense of be (am, is, are, was, were), add not after the verb.

For simple present-tense verbs other than be, use do or does plus not before the base form of the verb. (For the correct forms of do and does, see the chart on in 27c.)

For simple past-tense verbs other than be, use did plus not before the base form of the verb.

In a verb phrase consisting of one or more helping verbs and a present or past participle (is watching, were living, has played, could have been driven), use the word not after the first helping verb.

note: English allows only one negative in an independent clause to express a negative idea; using more than one is an error known as a double negative (see 26e for more on double negatives to express a positive idea).