If + past perfect + would have + verd (past participle)
If I had studied, I would have passed the test
I I hadn’t worked to much last month, I wouldn’t have burned out
If she had taken the earlier flight, she wouldn’t have arrived late
What would you have done differently ?
If he had known about the traffic, he would have arrived on time
If you had called me earlier, I would have been able to help you
If I had known that programing is an excellent tool, I would have learned earlier