Язык modal verb could + perfect ! example: he would have drowned! (it was possible for him to drown but it didn't happen). 1) you could have done it 10 times better 2) the boy could have passed his exams but that morning he was late because of the traffic jam! 3) they could have saved the man but the ambulance car came too late. 4) she could have won the prize but luck was againt her.

1) You would have done it 10 times better
2) The boy would have passed his exams ( if he hadn't been late because of the traffic)
3) They would have saved the man ( if the ambulance car hadn't come too late)
4) She would have won the prize ( if luck hadn't been against her)

Что вообще сделать-то надо было?