`1.` They visited Nha Trang with her parents last week. ( Thừa từ have)

`-` QKĐ (DHNB: last weekend):

S+V2/V-ed+O

`2.` My father is the oldest person.

`-` So sánh nhất:

S+be+ the + adj ngắn -est / most+ adj dài+ ...

`3.` Huong lives very far from her school.

`-` far from: xa

`4.` Where did you play tennis last weekend?

`-` QKĐ (DHNB: last weekend):

(?) Wh-words +did+S+ V-inf+O?

`5.` We're having a great time here in Cambodia!

`-` HTTD:

S+ is/am/are+V-ing+O

`6.` Maths is the most difficult subject in the school.

`-` tương tự câu `2`

`7.` Amsterdam is one of the most peaceful cities in the world.

`-` be one of the + adj ngắn -est/most+ adj dài + N-số nhiều : 1 trong những cái gì đó như thế nào nhất 

`8.` Ha Noi is the most peaceful city in the world.

`-` tương tự câu `2` và `6` 

`9.` If we throw trash on the road, we will pollute our environment.

`-` If `1`:

If+ HTĐ, + S+ will/can/should+V-inf+O

1. `@` They have visited Nha Trang with their parents last week.

  `-` HTHT : S `+` have/has `+` Vp2 `+` O .

2. `@` My father is the oldest person.

  `-` So sánh nhất : the adj/adv -est

  `-` My father : bố tôi (danh từ số ít)

3. `@` Huong lives very far from her school.

  `-` Far from sb/st : xa với ai/cái gì

  `-` HTĐ : S `+` V(s/es) `+` O .

4. `@` Where did you play tennis last weekend?

  `-` QKĐ : S `+` Ved/p1 `+` O .

  `-` last weekend : cuối tuần trước

5. `@` We're having a great time here in Cambodia! 

  `-` HTTD : S `+` tobe `+` V -ing `+` O .

6. `@` Maths is the most difficult subject in the school.

  `-` So sánh nhất : the most adj/adv

  `-` Maths (n) : môn Toán

7. `@` Amsterdam is one of the most peaceful cities in the world.

  `-` So sánh nhất : the most adj/adv

8. `@` Ha noi is the most peaceful city in the world.

 `-` So sánh nhất : the most adj/adv

9. `@` If we throw trash on the road,we will pollute our environment.

 `-` Câu điều kiện loại 1 : If `+` S `+` V(s/es) , S `+` will/shall/can `+` V .

 `-` Nếu vứt rác xuống đường `->` làm ô nhiễm môi trường.