English relies on the auxiliary verbs “to do” and “to be” to express negation. Which verb to use will often depend on if the action is past, present, or future. 

Present Tense

With “Do” 

The auxiliary verb “do” plus the word not is used to form negative statements in the present tense, except for when the subject is third person singular. This is often contracted from do not to “don’t”. For example:

  • I don’t like ice cream. (singular subject, “I”)
  • You don’t eat meat. (singular subject, “you”)
  • We don’t eat meat. (plural subject, “we”)
  • They don’t eat meat. (plural subject, “they”)

The auxiliary verb “does” is used to form negative statements in the present tense when the subject is a third person singular noun or pronoun (like “he,”  “she,” or “it”). It is often contracted from does not to “doesn’t”. Here are some examples:

  • She doesn’t eat meat. (third person singular subject, “she”)
  • It doesn’t eat meat. (third person singular subject, “it”)

With “Be”

To express negation using “to be” and “not,” the “not” must be placed after the “to be” verb. For example, if you want to negate the statement “I am happy,” you would say “I am not happy.” If you want to negate the statement “She is tired,” you would say “She is not tired.”

The negated forms of “to be” are usually contracted in spoken English. They can be contracted in two ways. One is by combining the subject and the verb. For example: 

  • “I’m not” (I am not)
  • “You’re not” (You are not)
  • “He’s not” (He is not)
  • “She’s not” (She is not)
  • “It’s not” (It is not)
  • “We’re not” (We are not)
  • “They’re not” (They are not)

Alternatively, the contraction can be made with the verb “to be” and “not”. As an exception, this form doesn’t exist for the subject “I” because no contraction of “am” and “not” exists in modern English.  

  • “You aren’t” (You are not)
  • “He isn’t” (He is not)
  • “She isn’t” (She is not)
  • “It isn’t” (It is not)
  • “We aren’t” (We are not)
  • “They aren’t” (They are not)

Past Tense

    With “Do”

    In the past tense “do” can be conjugated as did not, which is often contracted to “didn’t”. For example:

    • I didn’t like ice cream. (past tense, singular subject, “I”)
    • She didn’t eat meat. (past tense, third person singular subject, “she”)

    With “Be”

    To create negation in the past tense using the verb “to be,” the word “not” is placed directly after the past forms of “to be.” For example: 

    • I was not feeling well yesterday.
    • She was not at the party last night.
    • We were not interested in that movie.

    Future Tense

    Only the verb “to be” can be used for future tense negation. There is no future conjugation of the verb “to do”. To express negation in the future English uses “will” plus “not” which is often contracted to “won’t”. For example: 

    • She won’t go to the pool tomorrow. 
    • We won’t go on a hike this weekend. 

    Alternatively, future negation can also be expressed using the simple continuous verb tense. Although the verb is conjugated in the present, it is used to talk about future events. For example: 

    • She isn’t going to the pool tomorrow. 
    • We aren’t going hiking this weekend.