Formation of the present simple of ‘to do’

The verb ‘to do’ is regular when it is conjugated in the present simple and so it has two distinct forms. One form is the same as the infinitive of the verb (hence no differences between both forms) whereas the form in the third person singular requires ‘-es’ at the end of the verb. The ending ‘-es’ is a bit special as most of the English verbs just receive an ‘-s’. Furthermore, ‘to do’ is one of the three auxiliary verbs in English (be, do, have), but can also be used as a main verb. When it is employed as an auxiliary verb, it generally helps to compose negative sentence structures as well as interrogative structures (questions). However, it can also intensify statements. Compare:

1. Be careful: Only when used in the 3rd person singular the verb ‘to do’ takes ‘-es’ at the end of the verb and so converts to ‘does’. Moreover, there is also a change in pronunciation from ‘do’ [duː] to ‘does’ [dəz].
2. Examples of the use of ‘to do’ as main verb. As an English learner be careful to mind the difference of ‘do’ & ‘make’:
   • “I do sports every week.”
   • “Peter always does his homework.”
   • “It’s hot in here. Let me open the window. – Wait, I’ll do it.”
     • repetition of a verb that has been mentioned in the previous part (here the future simple with ‘will’)
3. If the verb ‘to do’ is used as an auxiliary verb, it appears in negative sentences and questions in most cases. Occasionally it is also utilized in statements when it serves to reinforce a statement, which means if someone wants to express certainty:
   • “She doesn’t like cold coffee.”
     • negation in the present simple
   • “Do Mary and James usually go on vacation in summer?”
     • question in the present simple
   • “Do you do the laundry every day? – No, I don’t do it every day, just once a week.”
     • question and negation together with ‘to do’ as main verb
   • “I’ll throw it away, you don’t need it anyway. – Of course, I do need it.”
     • reinforcement to strengthen the statement or claim
4. Attention: Mind that the verb forms of ‘to do’ always stay the same (means unchanged) – whether as auxiliary or as main verb. Additionally to that, ‘to do’ as auxiliary verb is also needed for negations and questions if ‘to do’ is used as a main verb. Compare the detailed conjugation in the following table:

Verb forms of ‘to do’ in the present simple (as auxiliary and main verb)

The table shows the verb ‘to do’ with all its possible forms as auxiliary and main verb in the present simple:

Positive/affirmative sentences

Negative sentences

Further explanations relating to the ‘Formation of ‘to do’ in the present simple’

The following explanations relate to the topic ‘Forming and conjugating ‘to do’ in the simple present’ and can be helpful:

• Explanation of singular and plural
• Using the present simple
• Formation of the present simple
• Formation & verb forms of ‘to have’ in the present simple
• Formation & verb forms of ‘to be’ in the present simple