This exercise is designed to help you practice the FORM of second, third and mixed conditionals. The forms are:
Note - V.1 means the first form of the verb (go=v.1, went=v.2, gone=v.3)
Second conditional: "If + simple past, would + V.1"
Third conditional: "If + past perfect (had + V.3), would + have + v.3"
Mixed conditional: (combines 2nd and 3rd conditional forms) "If + past perfect, would + v.1"

Rewrite the verb [within the square brackets] to complete the conditional sentence.
(DO NOT USE CONTRACTIONS i.e. "hadn't")