1. Who help people have better conditions ? 

2. What have children done ? 

3. Why children shouldn't use social network too much ?

4. What do local people depend on ?

5. How did he write the letter last week ?

6. How often does the festival take place ?

7. How long did the flight to Singapor take last month ?

8. What can noise pollution cause ?

9. What can lead to breathing pollution ?

10. Where did the villager use to collect water ? 

Công thức thì HTHT

(+) S + has/have + V3/ed 

(-) S + has/have + not + V3/ed 

(?) Has/Have + S+ V3/ed?

DHNB: before, since + mốc thời gian, for + khoảng thời gian, yet, already, just,....

Công thức thì HTĐ (V: thường)

S số ít, he, she, it 

(+) S + Vs/es

(-) S+ doesn't + V1 

(?) Does +S +V1?

S số nhiều, I, you, we, they

(+) S + V1 

(-) S+ don't + V1 

(?) Do + S+ V1? 

DHNB: always, usually, sometimes, often, never, seldom,....

Công thức thì QKĐ (V: thường)

(+) S + V2/ed 

(-) S + didn't + V1 

(?) Did + S+ V1?

DHNB: ago, last (year, month ...), yesterday, in + năm QK, ...

-------------------------------------------------

Wh + should + S +V1? 

Wh + can + S+ V1? 

-------------------------------------------------

Who: ai

What: cái gì

Why: tại sao

How: như thế nào 

How often: tần suất 

How long: bao lâu 

Where: ở đâu

When: khi nào 

-------------------------------------------------

1. What helps people have better conditions?

2. What have the children done?

3. Why shouldn't children use social network too much?

4. How do local people depend on tourism?

5. How did he write the letter last week?

6. How often / When does the festival take place?

7. How long did the flight to Singapore take last month?

8. What can noise pollution cause?

9. What can lead to breathing problem?

10. Where did the villagers use to collect water from?

`color{orange}{~MiaMB~}`