`36.` Ho Chi Minh City is the most crowded city in Viet Nam.

`->` So sánh nhất 

`37.`This is the first time I have visited this beautiful place.

`->` This is the first time + S + have/has + V3

`<=>`  S+ have/has not + V3 + before

`38.` We have never won a big match before.

`->` Tương tự câu `37.`

`39`. They last saw him `2` week ago. 

`->` They haven't seen him for `2` weeks. 

`->` S + last +V3 + khoảng thời gian + ago

`<=>`  S + have/ has + not +V3+ for + khoảng thời gian

`40.` They started learning English in `2000.`

`->`  They have learnt English since `2000.`

`->` S + started + V-ing/to V + in + mốc thời gian trong quá khứ

`<=>` S + have + V3 + since + mốc thời gian trong quá khứ

36. Ho Chi Minh City is the most crowded city in Viet Nam.

37. This is the first time I have visited the beautiful place.

38. We have never won a big match before.

39. They haven't seen him for two weeks

40. They have learnt English since 2000.

Xin lỗi bn nhé, tại nhà mất điện nên mik lm hơi chậm