Only when he left his hometown and went abroad he loved his parents very much.
A. has he realized
B. did he realize
C. he realized
D. he had realized
网友回答
A. has he realized
(答案→)B. did he realize
C. he realized
D. he had realized
解析：考查only引导的倒装。Only放在句首，且强调状语的时候，后面的句子使用部分倒装。本题符合条件，Only放在了句首，强调了状语从句when he left his hometown and went abroad故后面使用部分倒装，排除CD。根据本题没有用出现现在完成时的时间状语，排除了A。句意：只有当他离开家乡出国的时候，他才意识到自己是多么的热爱他的父母。故B正确。