Question

Only when I made it to the train station _______ that I had left my ticket at home.

A．have I realized

B．did I realize

C．had I realized

D．would I realize

Answer 1

B

考查倒装句。Only +状语放在句首，使用部分倒装。从句不倒装，主句倒装。此题是Only+时间状语放在句首，根据时态应选B。