问题
选择题
Only when _______ home_____ that he had left his bag in the taxi he had taken.
A．he returned; did he realize
B．did he return; did he realize
C．he returned; he realized
D．did he return; he realized
答案
答案：A
考查倒装。Only + 状语从句，从句不倒装，主句的主谓要倒装，，故选A。