Cấu trúc chung :

S + started / began + V-ing / to V + when + S + V-ed / V2

= S + have / has + VPII + since + 1 mốc TG / QKĐ

Hoặc

S + started / began + V-ing / to V + 1 khoảng TG + ago

= S + have / has + VPII + for + 1 khoảng TG

1 : I have lived in Ho Chi Minh city since i was 8 

2 : She started teaching the children in this remote villige 5 years ago

3 : She has driven for 1 month

4 : We have eaten since it started to rain

5 : We have been looking for a flat for 2 months 

Câu này ta chia thì HTHTTD : 

S + have / has + been + V-ing

Vì vế sau có nói : And we are still looking 

Mà thì HTHTTD dùng để diễn tả hành động xảy ra trong quá khứ nhưng vẫn tiếp tục ở hiện tại và nó có thể vẫn sẽ xảy ra / tiếp diễn trong tương lai 

1)i have  lived in HCM city since i was 8

2)she started teaching in this 5 months ago

3)she has driven for 1 month

4)we have eaten since it started to rain

5) we have been looking for a lat for two months