did and do

We use do when the subject is I, you, we or they.
Does she like sport? Yes, she does.

  1. To add emphasis to an entire sentence: “He does like spinach. He really does!”
  2. To add emphasis to an imperative: ” Do come in.” (actually softens the command)
  3. To add emphasis to a frequency adverb: “He never did understand his father.” “She always does manage to hurt her mother’s feelings.”
  4. To contradict a negative statement: “You didn’t do your homework, did you?” “Oh, but I did finish it.”
  5. To ask a clarifying question about a previous negative statement: “Ridwell didn’t take the tools.” “Then who did take the tools?”
  6. 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 and do, Language Skills Abroad
The word DO appears a lot in English.
To make a negative sentence in English we normally use Don’t or Doesn’t in the present sentence.

  • I do my laundry on Saturdays.

(Chores is the housework you need to do like washing the dishes, doing the vacuuming, etc.)

did and do, Language Skills Abroad
He does not ___
They didn’t have any money last week. (past tense negative.)

Resources:

http://www.english-for-students.com/Does-and-Did.html
http://www.grammar.cl/english/do-does-did-done.htm
http://www.woodwardenglish.com/lesson/do-does-did-done/
http://www.learnamericanenglishonline.com/Red%20Level/R3%20Do%20and%20Did.html
http://membean.com/wrotds/dis-apart