Introduction
An auxiliary verb is a helping verb that has no meaning on its own but it gives functional and grammatical meaning to the main verb.
Do can be both a main verb and an auxiliary verb. Do as a main verb is used to perform or to complete an action.
Do as an auxiliary verb is used to form the negative and interrogative sentences of other verbs, as well as for emphasis and negative imperatives.
Form
The verb do as an auxiliary verb is followed by infinitives without to.
It can have three forms: present, past and imperative.
Present form
In its present form it has three forms:
- Affirmative: it is used for emphasis:
Subject + do/does + base form of the verb… - Negative:
Subject + do/does + not + base form of the verb… - Interrogative:
Do/does + subject + base form of the verb…?
Past form
In its past form, it has three forms:
- Affirmative (for emphasis):
Subject + did + base form of the verb… - Negative:
Subject + did + not + base form of the verb… - Interrogative
Did + subject + base form of the verb…?
Imperative form
It can be negative and only in the present tense:
Do + verb (infinitive without to) + …
Example
- To form negatives of other verbs:
- I don’t speak Spanish.
- I didn’t hurt my neck.
- To form interrogative sentences of other verbs:
- Do you like swimming?
- Did you heard the news?
- To give emphasis in an affirmative clause:
- She does look nice today.
- She did break her leg yesterday.
- To form negative imperatives in its negative form (don’t):
- Don’t speak loudly!
- Don’t ever come back!
Use
Do as an auxiliary verb is used:
- to form negatives of other verbs;
- to form interrogative sentences of other verbs;
- to give emphasis in an affirmative clause;
- to form negative imperatives in its negative form (don’t).
Summary
— Interrogatives: “Do/Did you live in Brussels?” = Do as an auxiliary verb is put before the subject to create an interrogative.
— Negative: “I don’t/didn’t like football.” = We use do as an auxiliary verb before the main verb to form a negative sentence.
— Emphasis: “You do/did look tired.” = We use do as an auxiliary verb before the main verb in an affirmative sentence to give emphasis.
— Negative imperative: “Don’t talk to me!” = Do in the negative form is used to form a negative imperative.
NOTE: We always use the negative form (don’t) for negative imperatives and it is always put at the beginning of the sentence.
Let’s revise this content in {Form} section. Take a look at {Example} section that shows its use within a context sentence.