giúp mk với các bạn

`15`. Lan didn't write to Maryam a month ago.

`->` Câu nghi vấn thì quá khứ: S + did + not + Vinf

`16`. He started living in Ha Noi when he was 12.

`->` S + started + Ving + when + S2 + V2/ed = S + have/has + Vpp + since + S2 + V2/ed

`17`. I didn't meet her a long time ago. ( giống câu 15 )

`18`. How long ago did you learn French?

`19`. When did you buy this car?

`20`. How long have you listened to classical music?

`21`. I haven't seen her for 10 years.

`->` S + last + V2/ed + thời gian + ago = S + have/has + not + Vpp + for + khoảng thời gian