had I been able to get a ticket ,I would have gone to the concert这是什么句型时态各是什么 为什么 等

题目

had I been able to get a ticket ,I would have gone to the concert这是什么句型时态各是什么 为什么 等

答案

have/has been done 是现在完成时的被动语态.表示某事被做.
虚拟语气的句子配套使用：主句had done +从句would have done
前半句是现在完成时态,后半句是虚拟语气.