Negative Statements and Questions

In many languages, changing a statement to a question is as easy as changing your inflection or punctuation. In Spanish, for example, you can say, “Ella habla Inglés,” or you can ask, “¿Ella habla Inglés?” The word order does not change. In English, however, the statement is, “She speaks English,” whereas the question changes to, “Does she speak English?” English questions almost always use an auxiliary verb.

Negative statements in English also generally use an auxiliary verb. We can’t just say, “They liked the soup?” We have to rearrange a bit, adding in the past form of the auxiliary “do” to say, “Did they like the soup?”

Do / does / did

Do is common for forming questions and making negatives.
Did is used for do and does in the past tense. Do and does is never used for the past.

In statements In questions In negative sentences
I am 21. Am I in the right place? I am not. (I aren't)
You are Indian. Are you my new boss? You are not. (you aren't)
We are waiting. Are we nearly there? We are not. (we aren't)
They are excited Are they the best players on the team? They are not. (they aren't)
He/she is cool. Is he/she old enough to go to bars? He/she is not. (he/she isn't)

Be = am / is / are

Be can be used as an auxiliary verb or the main verb in a sentence.
Is tells us that an action is happening now or is going to happen in the future.
Be is also used to make passives.
Are is used for they and we.
Was is used for the past tense of am and is.
Were is used for the past tense of you, we and they.

In statements In questions In negative sentences
I do my homework. Do I know you? I do not. (I don't)
You do the laundry. Do you live here? You do not. (you don't)
We do the washing up. Do we have time? We do not. (we don't)
They do yoga. Do they come from Vietnam? They do not. (they don't)
He/she does the cleaning. Does he/she drive to work? He/she does not. (he/she doesn't)

Have = has / had

Have is used to make the present perfect tense (it is always followed by the past participle).
Has is used for the third person singular.
Had is used for past tenses especially the past perfect tense. It describes an action that began in the past and continues into the present or that occurred in the recent past.

In statements In negative sentences
I have a dog. I have not. (I haven't/ I've not)
You have something on your shirt. You have not. (you haven't/you've not)
We have seen it before. We have not. (we haven't/we've not)
They have called me three times. They have not. (they haven't/they've not)
He/she has lived in America. He/she has not (he/she hasn't)

Others

Other common auxiliary verbs are:
can, could, may, might, must, ought, should, and would.
These are also known as modal verbs. We use them to show obligation, possibility and necessity.