1. Why did you go to Ha Noi City?

(What for = Why: hỏi mục đích)

2. When did you build this stilt house?

(How long is it since + S + V-qk = When + did + S + V-inf: hỏi thời điểm của việc gì)

3. How long is it since you moved to Ha Noi City.

(How long is it since + S + V-qk = When + did + S + V-inf: hỏi thời điểm của việc gì)

4. What is his address?

(Where + do/does + S + live = What is + address: hỏi địa chỉ ở)

5. Duong should go to Bac Ninh to see the Lim Festival.

(What about + Ving = should + V-inf: lời gợi ý/rủ)

6. Although he studied very hard, he still didn't pass the exam.

(Dùng Although trước vế xảy ra trước: mặc dù đã học rất chăm -> vẫn không qua kỳ thi)

$1.$ Why did you go to Ha Noi City?

- What for = Why: hỏi lí do xảy ra hành động.

- Did + S + V (Bare)?

$2.$ When did you build this stilt house?

- When + did + S + V (Bare) = How long + have/ has + S + V3?

$3.$ How long is it since you moved to Ha Noi City.

- Giống như câu $2$ ạ.

$4.$ What is his address?

- Where + do/ does + S + live = What is + someone's address: hỏi địa chỉ.

$5.$ Duong should go to Bac Ninh to see the Lim Festival.

- What about + V-ing? = S + should + V (Bare): đưa ra đề xuất làm việc gì.

$6.$ Although he studied very hard, he still didn't pass the exam.

- Although + S + V: Mặc dù ...

- Nêu lên sự đối lập giữa hai mệnh đề.