Uses of Do, Does and Did :
In the simple present tense, do will function as an auxiliary to express the negative and to ask questions. (Does, however, is substituted for third-person, singular subjects in the present tense. The past tense did works with all persons, singular and plural.)
- I don't study at night.
- She doesn't work here anymore.
- Do you attend this school?
- Does he work here?
These verbs also work as "short answers," with the main verb omitted.
Does she work here? No, she doesn't
With "yes-no" questions, the form of do goes in front of the subject and the main verb comes after the subject:
Did your grandmother know Truman?
Do wildflowers grow in your back yard?
Forms of do are useful in expressing similarity and differences in conjunction with so and neither.
- My wife hates spinach and so does my son.
- My wife doesn't like spinach; neither do I.
Do is also helpful because it means you don't have to repeat the verb:
Larry excelled in language studies; so did his brother.
Raoul studies as hard as his sister does.
The so-called emphatic do has many uses in English.
To add emphasis to an entire sentence: "He does like spinach. He really does!"
To add emphasis to an imperative: "Do come in." (actually softens the command)
To add emphasis to a frequency adverb: "He never did understand his father." "She always does manage to hurt her mother's feelings."
To contradict a negative statement: "You didn't do your homework, did you?" "Oh, but I did finish it."
To ask a clarifying question about a previous negative statement: "Ridwell didn't take the tools." "Then who did take the tools?"
To indicate a strong concession: "Although the Clintons denied any wrong-doing, they did return some of the gifts."
In the absence of other modal auxiliaries, a form of do is used in question and negative constructions known as the get passive:
Did Rinaldo get selected by the committee?
The audience didn't get riled up by the politician.
Related Pages :
Shall and Will and Should
Do, Does and Did
Have, Has and Had
Can and Could
May and Might
Will and Would