`6.` I started learning English 5 years ago.

`→`S + have/has + VPII + for/since + thời gian

`=` S + started/began + VING/TO V + thời gian

`7.` They started working on this project 2 weeks ago.

`→`S + have/has + VPII + for/since + thời gian

`=` S + started/began + VING/TO V + thời gian

`8.`It's a month since Tom last played games.

`⇒`The last time Tom played games was a month ago.

`→` Phủ định của hiện tại hoàn thành : S + have/has not + VPII + for/since thời gian

`=` It’s + time + since + S + last + V2/ed + O

`=` The last time (Lần cuối cùng) + S last + V quá khứ + was + time + ago

`9.` It's 5 years since they last visited their hometown.

`⇒`The last time they visited their hometown was 5 years ago.

`→` Phủ định của hiện tại hoàn thành : S + have/has not + VPII + for/since thời gian

`=` It’s + time + since + S + last + V2/ed + O

`=` The last time (Lần cuối cùng) + S last + V quá khứ + was + time + ago

`10.` How long has she been away from home?

`⇒`How long is it since she was away from home?

`→`How long + have/has + S + VpII ?

`=` How long is it since + S + V quá khứ ?