What Would Have Happened
Third Conditional
The third, or 'past', conditional is used to imagine past outcomes different than what actually took place. This conditional is used to express what would have been different if a person had done something differently.
'If' clause - past perfect + , + result clause - would + have + verb (conditional perfect tense)
Examples of Past Unreal Outcomes
He wouldn't have signed the lease agreement if he had corresponded with his advisor.
He would have invested in the futures market if he'd had more confidence in the economy.
Payments on the student loan's deferred interest would not have been a problem if the economy had been better.
If the homebuilder had predicted the speculative bubble they would have laid off more employees.
Do not use a comma, when placing the result clause first.
He would have invested in the futures market if he'd had more confidence in the economy.
She would have ordered the TV online if the shipping cost had been lower.