“Do” is the base verb used to talk about actions, to form questions and negatives in the present and past simple, and to add emphasis. “Does” is the present simple form for he, she, it. “Did” is the past simple form for all subjects. “Done” is the past participle used with auxiliary verbs like “have” and in the passive.

Use “do” as a main verb to mean perform an action, carry out work, or complete a task. In this meaning, it can take an object like “homework,” “the dishes,” or “a job.” The tense and form change with time and subject: do, does, did, have done.

In the present simple, use “do” with I, you, we, they, and use “does” with he, she, it. This applies both when “do” is the main verb and when it is an auxiliary in questions and negatives. The main verb after auxiliary do or does stays in the base form.

Subject	Form	Example
I	do	I do my homework after dinner.
you	do	You do a great job.
he	does	He does the dishes.
she	does	She does yoga every morning.
it	does	It does not matter.
we	do	We do our best.
they	do	They do the cleaning on weekends.

Use “did” for the past simple with all subjects. When “did” is an auxiliary, the main verb remains in the base form, not the past form. This is a common pattern in questions and negatives about the past.

Subject	Form	Example
I	did	I did my homework yesterday.
you	did	You did well on the test.
he	did	He did not call last night.
she	did	She did her best.
it	did	It did not work.
we	did	We did the shopping on Saturday.
they	did	They did not agree.

“Done” is the past participle of “do.” Use it with auxiliary verbs like “have” to form perfect tenses, and with “be” in passive structures. “Done” does not replace “did” in the simple past.

Rule	Example
Use have or has with done for present perfect	I have done my homework.
Use had with done for past perfect	They had done the work before noon.
Use be with done for passive voice	The job is done.

Use do or does to form present simple questions, and did to form past simple questions. In these questions, the main verb stays in the base form. If “do” is the main verb, you still use do or does or did, but the structure depends on whether you are asking about the action or using “do” as an auxiliary.

Rule	Example
Present simple questions use do or does plus base verb	Do you like coffee.
Third person present uses does plus base verb	Does she work here.
Past simple questions use did plus base verb	Did they finish on time.

Use do not or does not in present simple negatives, and did not in past simple negatives. The main verb stays in the base form after do, does, or did. In speech and informal writing, contractions are common: don’t, doesn’t, didn’t.

Rule	Example
Present negative uses do not or does not plus base verb	I do not know.
Third person present uses does not plus base verb	He does not understand.
Past negative uses did not plus base verb	We did not go.

Use do, does, or did for emphasis in affirmative sentences, usually to correct someone or strongly confirm something. The emphasized verb after do, does, or did remains in the base form. This is more common in speech and can sound confrontational if overused.

Rule	Example
Use do or does to emphasize a present statement	I do want to help.
Use did to emphasize a past statement	She did call you.

Use do, does, and did in short answers to yes or no questions. Match the tense and subject of the question, and choose do or does for the present. Negative short answers use the contracted form in most everyday contexts.

Rule	Example
Match do or does in present short answers	Does he live here. Yes, he does.
Use did for past short answers	Did you see it. No, I didn’t.
Use do for I, you, we, they	Do they agree. Yes, they do.

“Done” can function like an adjective to mean finished, completed, or no longer needed. This usage often appears after “be” or in set phrases, and it focuses on the state, not the action. It is common in everyday speech.

Rule	Example
Use be plus done to express completion	I’m done with my work.
Use all done as an informal phrase	We’re all done.