How to use auxiliary verbs correctly in English
Why they think this? [incorrect]Why do they think this? [correct]
I not agree with this idea. [incorrect
I do not agree with this idea. [correct]
Do, be and have are called auxiliary verbs.
This means that they help to change the main verb.
Do is used with the infinitive to make negatives or questions:
I don't agree. (not
Do you agree? (not
Do can be used with other question words:
Why do you agree? (not
Be is used with -ing verb forms to make the continuous tenses:
I am studying English in Cambridge. (not
Have is used with the past participle of the verb to make the perfect tenses:
I have been here for three months. (not
The auxiliary verb must agree with the subject of the verb:
Does your mother drink tea? (not
We make questions and negatives without do if another auxiliary verb is used:
Are you studying here? (not
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