`6.` I haven't spoken to her for three years.

 - It's + time + since + S + (last) + V2/ed

`->` S + have/has not + V3/ed + since/ for + mốc thời gian/ khoảng thời gian.

`-` The last time I spoke to her was three years.

`->` The last time + S + V2/ed + was + mốc thời gian/ khoảng thời gian.

`-` I last spoke to her three years ago.

`->` S + last + V2/ed + khoảng thời gian + ago. 

`7.` They have used this car since `2015.`

  - S + started/ began + V-ing/ to V + time

`->` S + have/has + V2/ed + since/ for + mốc thời gian/ khoảng thời gian

`8.` I have never used a better computer than this.

   - It/ This is the best ... + S + have ever + V3/ed

`->` S + have never + V3/ed + ... + than this. 

`9.` He last chatted with his classmates through the internet `2` weeks ago. 

   - S + have/has not + V3/ed + since/ for + mốc thời gian/ khoảng thời gian.

`->` S + last + V2/ed + khoảng thời gian + ago. 

`-` The last time he chatted with his classmates through the internet was `2` weeks. 

`->` The last time + S + V2/ed + was + mốc thời gian/ khoảng thời gian.

`-` It is `2` weeks since he last chatted with his classmates through the internet.

`->` It's + time + since + S + (last) + V2/ed

`10.` This is the first time he has played a computer game. 

   - S + have/has never + V3/ed + before

`->` It/ This is the first time + S + have/has + V3/ed 

`11.` The last time we saw her was when we left university.

   - S + have/has not + V3/ed + since/ for + mốc thời gian/ khoảng thời gian

 `->` The last time + S + V2/ed + was + when + S + V2/ed

`-` We last saw her when we left university.

`->` S + last + V2/ed + when + S + V2/ed

`12.` I have never played a computer game before

    -  It/ This is the first time + S + have/has + V3/ed 

`->` S + have/has never + V3/ed + before. 

`\color{green}{#Queen}`

`7.` They have been used this car since 2015

`-` $\text{S + started/began + to do sth + in + year}$ 

`=>` $\text{S + have/has + not + VpII + for + time}$

`8.` I have never used the best computer before.

`-` $\text{This is the first time + S + have/has + VpII}$ 

`=>` $\text{S + have/has + never + VpII + before.}$

`9.` He last chatted with his classmates through the internet 2 weeks ago

`-` $\text{S + have/has + not + VpII + for + time}$

`=>` $\text{S + last + V-ed + time + ago}$

     The last time he chatted with his classmates through the internet was 2 weeks ago

`-` $\text{S + have/has + not + VpII + for + time}$

`=>` $\text{The last time+ S + V-ed + was + time + ago}$

     It is 2 weeks since he last chatted with his classmates through the internet

`-` $\text{S + have/has + not + VpII + for + time}$

`=>` $\text{It is + time + since + S + (last) + V-ed}$

`10.` This is the first time he has played a computer game

`-` $\text{S + have/has + never + VpII + before.}$

`=>` $\text{This is the first time + S + have/has + VpII}$ 

`11.` The last time we saw her was we left university 

`-` $\text{S + have/has + not + VpII + since + time}$

`=>` $\text{The last time + S + V-ed + was + time + ago}$ 

     We last saw her when we left university

`-` $\text{S + have/has + not + VpII + since + time}$

`=>` $\text{S + last + V-ed + time + ago}$

`12.` I have never played a computer game before

`-` $\text{This is the first time + S + have/has + VpII}$ 

`=>` $\text{S + have/has + never + VpII + before.}$