The verb DO plays an enormous role in the English language. It is the most important verb after BE. The primary function of DO is as an auxiliary verb. In this role it is used to form questions and negative statements.
The verb DO can also be used as a main verb, as explained in this lesson.
Like all English verbs, except BE and modal verbs, the verb DO has two conjugations in the simple present: do | does.
|third person||he, she, it||does||they||do|
Note that the third person singular form of the verb has -es added. All the other conjugations are do.
In fact, use of the verb DO as a main verb in the simple present is very limited. Its only purpose is to indicate who or what performs a habitual action or task. For example:
|He does his homework at night.|
|We do it all the time.|
|The car does this when it is cold.|
|Machines do the difficult work.|
Occasionally the verb DO is used as an auxiliary verb in affirmative statements in order to make a contradiction. For example:
|Tom drinks tea. He doesn’t drink coffee.||Yes, Tom does drink coffee.|
|I’m sorry, I don’t have a pen.||Oh, I do have a pen! Here.|
|Susan doesn’t smoke.||You’re wrong. Susan does smoke.|
In the above examples, DO is stressed.
The verb DO has a single conjugation for all persons in the simple past: did.
|3rd per||he, she, it||did||they||did|
Here are examples with DO used as a main verb in the simple past.
|I did the dishes last night.|
|Tom did the cleaning of the house.|
|We did a tour of the city.|
|Your idea did help, a little.|
Note that in the simple past, did refers to a single action. It does not indicate a habitual action. Again, the use of DO, when used in the simple past, is very limited. There is always another verb that is more precise.
|less precise||more precise|
|I did the dishes last night.||I washed the dishes last night.|
|Tom did the cleaning of the house.||Tom cleaned the house.|
|We did a tour of the city.||We went on a tour of the city.|
|Your idea did help, a little.||Your idea helped, a little.|
Remember, DO functions primarily as an auxiliary verb. Click on the related lessons below to learn more about this very important verb.