"Did you eat breakfast?" So that is how you can understand why the "did" is there. It's an auxiliary which is inserted to replace a null auxiliary once subject-aux inversion takes place (do affixing), and at the same time "steals" the past tense from the main verb, because auxiliaries have to carry the tense when they are present!

2022年11月7日 · It is part of a contrastive 'rebuttal' construction. If you say | I did do Spanish for four years, it emphatically contrasts with the idea that you didn't do Spanish, or didn't do it for very long.

Well, Do be quiet! is certainly a natural imperative construction. And although I wouldn't like to stake my life on it, I doubt there are any syntactic errors in something like Does he be quiet when he's told to shut up? (but there might be a rule saying why Yes, he certainly does be quiet! isn't an acceptable response).

2018年3月20日 · A question beginning with did is enough to turn the entire sentence into a question asking about something that happened in the past. All subsequent verbs in the sentence keep their "present tense" form. Do you want to schedule a meeting? It's exactly the same thing here, but instead of did (past) you're using do (present).

2021年11月29日 · No one knew what I did. No one knew what I had done. Which sentence is grammatically correct and what's the difference between them?

2016年4月20日 · "I did" is the "simple past" form.We use the Simple Past to express the idea that an action started and finished at a specific time in the past. Sometimes, the speaker may not actually mention the specific time, but they do have one specific time in mind.

2017年5月30日 · The first sentence " How did you solve the problem? " is a perfectly structured and grammatically correct interrogative sentence that is in the past tense. The second sentence " How you solved the problem? " is bad English. It may be said by some non-native speakers who are just learning English.

When speaking in the present tense, should I use former or the latter? Should I leave? But if I do/did that, she will (would?) spend the rest of the night drinking alone I checked if I do that an...

2022年2月24日 · Examples: She knew he wouldn't open the door—but when he did/did so, she had to be prepared. She looked at the alley. No matter how long she did/did so, he wouldn't show up. Should it be did or did so in situations like these?

2025年1月11日 · What do you mean by It couldn't have been done by anybody but him? That could be interpreted two ways - "He is the only person who could have done it" (a deduction about the past) or "He was the only person able to do it" (a statement about a situation in the past). Otherwise, I agree with Stuart's answer.