`1` had been / would have played

`2` had gone / would have had

`3` would not have failed

`4` had not been

`5` had come / would not have died

`6` had been / would have understood

`7` had come / would have arrested

`8` would not have succeeded 

`9` had remembered

`10` had accepted / would not have regreted

`11` had been / would have taken 

`12` would not have happened / had not stopped

`13` had not been

`14` had known / would have gone

`15` had found

`=>` Cấu trúc câu đk loại `3` (  nói về một sự việc ĐÃ KHÔNG THỂ xảy ra trong quá khứ nếu có một điều kiện nào đó. ) 

`(+)` If + S + had + Vpp + ...... + S + would + have + Vpp + ......

`(-)` If + S + had not + Vpp + ...... + S + would + not + have + Vpp + ....