Grammar: When to Use Do, Does, and Did
  • 3-minute read
  • 12th August 2022

Grammar: When to Use Do, Does, and Did

Verbs are essential to creating complete sentences, as they help us express physical actions (She jumped in the puddle), mental actions (He thought about puppies), and states of being (I am hungry).

There are several types of verbs that can each be written in different tenses, so they can be tricky to work with, especially if English isn’t your first language. We’ve put together a guide to help you use one of the most common verbs, do, in your writing. Read on below to learn more!

Action Verbs

As the name suggests, action verbs are used to express actions completed by the subject of a sentence. The base verb do is conjugated according to the tense:

1. Present Tense

In the present tense, do takes the form do or does, depending on the subject:


Consider the following examples:

We do our homework every night.

   She does her homework every night.

2. Past Tense

In the simple past tense, the base verb do takes the form did with all subjects:


Consider the following examples:

   We did our homework last night.

   She did her homework last night.

Auxiliary Verbs

Auxiliary, or helping verbs, are used with another base verb to create negative sentences, questions, or add emphasis. Here’s how do should be used as an auxiliary verb:

1. Negative Sentences

Following the same subject–verb pairings introduced above, we combine the auxiliaries do, does, and did with the adverb not to create negative sentences:

   We do not do our homework every night.

   She did not do her homework last night.

Note that we can combine the auxiliary and the adverb to create the contractions don’t, doesn’t, and didn’t. You simply remove the space between the two words and replace the letter o in not with an apostrophe (’).

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Contractions are more common in conversations and informal writing and typically shouldn’t be used in formal writing (e.g., academic or business).

2. Questions

To create questions, the auxiliary is combined with the infinitive of another verb in this way: auxiliary verb + subject + infinitive verb.

●  Simple present questions:

Do they sell children’s books?

Does he speak English?

Note that the third person verb speaks isn’t spelled with the s when paired with the auxiliary to form a question.

●  Simple past questions:

Did you buy anything at the bookstore?

Did he learn how to speak English?

Note that did indicates the past tense, so the main verbs don’t also take the past tense (i.e., bought and learned).

3. Emphasis

In positive sentences, we can also combine the auxiliaries do, does, and did with the main verb to emphasize that something is true:

   We do sell children’s books.

   He did learn to speak English.

Try saying these sentences aloud and adding emphasis to the auxiliary terms with your tone. It adds a dramatic effect!

Proofreading and Editing Services

Hopefully, this guide will help you feel more confident when using different forms of the verb do in your writing. If you’re still learning or want to be sure your work is error-free, our editors are ready to help. You can upload a free trial document today to learn more!

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