Question

Only when I put myself in their position ________ they were more miserable than me.

A．I had known　B．had I known

C．I knew　D．did I know

 

Answer 1

D

【解析】句意：只有当我设身处地为他们想的时候，我才知道，他们比我更加痛苦。only＋状语从句位于句首时，主句要用部分倒装，know这个动作发生在put之后，所以不能用过去完成时，因此选D。