`8,` Scientists have fought against AIDS since 1980.

`@` S + started/began+V-ing/ to V +O + mốc thời gian.

`=` S+ has/have+ Vp2+O+ since+mốc thời gian.

`9,` The Browns began living in London 20 years ago.

`@` S+ has/have+ Vp2+O + for + khoảng thời gian.

`=` S + started/began+V-ing/ to V +O + khoảng thời gian + ago.

`10,` John started working in this electronics firm in 1999.

`@` Tương tự câu `8`

`11,` This is the first time my father has driven a car.

`@` S+ have/has + not + Vp2 + O + before. 

`=` This is the first time + S+ has/have + Vp2 + O.

`12,` It’s the first time I’ve met such a famous singer.

`@` S+ has/have+ never + Vp2 +O + before.

`=` It's the first time + S+ has/have + ( ever) +  Vp2 +O. 

`13,` This is the first time she has drunk Coca Cola.

`@` Tương tự câu `11`

`14,` I have never met such an intelligent student before.

`@` Tương tự câu `12` 

`15,` My grandfather has not visited Ha Long Bay before.

`@` Tương tự câu `11`