`12.` The last time I saw her was ten years ago

`-` Cấu trúc: The last time + S + V2/ed + was + khoảng thời gian/ mốc thời gian

`13.` Although cars cause pollution, people still want them

`-` Cấu trúc: Although + S + V

`14.` We started building this house 5 months ago

`-` Cấu trúc: S + started/ began + Ving + khoảng thời gian/ mốc thời gian

`15.` It is three years since I last saw Minh

`-` It is + khoảng thời gian + since + S + last + V2/ed

`16.` My sister has learnt English for 5 years

`-` Cấu trúc: S + have/has + VpII 

`-` My sister là số ít `->` has

`-` for + khoảng thời gian

`12`.The last time I saw her was ten years ago

`\rightarrow` Cấu trúc : The last time + S + Ved / V2 + was + time

`13`.Although cars cause pollution , people still want them

`\rightarrow` Although + C1 + C2 : Mặc dù

`14`.We started building this house 5 months ago

`\rightarrow` Cấu trúc : S + started / began + V-ing / to V + time

`15`.It is three years since I last saw Minh

`\rightarrow` It is + time + since + S + last + Ved / V2 : Đã là ... kể từ khi ...

`16`.My sister has learnt English for 5 years

`\rightarrow` Thì HTHT : S + have / has + V3 / PII

`\rightarrow` Đặc điểm nhận dạng : for

`\text{@ TheFox}`