Negative sentences are those which state something that is not true. In English grammar the general rule that defines a negative sentence is that the word ‘not’ appears after an auxiliary verb in the positive sentence. If there is no auxiliary verb in the positive sentence, then you add the auxiliary verb do.

Examples of negative sentences

The most common way to write a negative statement is the use of a negated auxiliary verb. An auxiliary verb is a verb that is used when in forming the tenses, moods, and voices of other verbs. ‘Be’ verbs are an example of an auxiliary verb. The ‘be’ verbs include:

To be (am, is, are ,was, were)

To have (have, has, had)

To do (do, does, did)

Look at the examples of negative sentences in different tenses. Note that some sentences use the contracted forms of informal writing and speech, and some others use the full forms

Positive sentence:   I sing

To create a negative sentence from this, let’s use this format: Tense + Negative Word or its Contracted Form.

If there is no auxiliary verb in the positive sentence, as in the Present Simple and Past Simple tenses, then you add one, such as the auxiliary verb, ‘do’.

Present Simple Tense

do+not = don’t

I do not sing = I don’t sing

does+not = doesn’t

She does not sing = She doesn’t sing

Past Simple Tense

did+not = didn’t sing

I/She didn’t sing

Here are the ways a negative sentence looks using other tenses:

Present Progressive

is+not = isn’t

She is not singing  = She isn’t singing

are+not = aren’t               

We are not singing = We aren’t singing

Past Progressive

was+not = wasn’t

I was not singing = I wasn’t singing

were+not = weren’t    

They were not playing = They weren’t playing

Present Perfect

have+not = haven’t   has+not = hasn’t   

You have not sung = You haven’t sung

She has not sung = She hasn’t sung

Besides the word ‘not’, the following are some of the negative words that can also be used use to create a negative sentence:

No

None

No one

Nobody

Nothing

Neither

Nowhere

Never

Lastly, a negative sentence is not the same as a double negative. In a double negative, the meaning is understood, but the sentence is not based on proper grammatical rules and usage. In fact, the meaning is exactly the opposite if you read a double negative in strict grammatical terms correctly.

The double negative is usually produced by combining the negative form of verb – did not, was not, etc. with a negative pronoun such as nothing:

I didn’t do nothing.
I didn’t see nobody.

These sentences really mean something positive, i.e.:

I did do something.
I saw somebody.

A double negative is not actually a negative sentence, but a positive one!