`9.`Tom has been able to drive since he was nineteen.
`→`S + learn/study + to V + when + time
`=`S + have/has been able to + V + since/for + time
`10.`Despite having all the necessary qualifications, they didn’t offer me the job.
`→`Although S + V + O , clause 2 `=` In spite of / Despite + N/Ving, clause 2
`11.`Since the computer was invented, people have saved a lot of time.
`→`Bị động quá khứ đơn : S + was/were + VpII + (by O)
`12.`After Lan had said goodbye to her parents, she went to school.
`→`After + S + had V2/ed, S + V2/ed