Only when he failed in the final exam up his mind to study harder to catch up with the classmates ahead of him.
A. he made
B. he had made
C. had he made
D. did he make
网友回答
A. he made
B. he had made
C. had he made
(答案→)D. did he make
解析：考查倒装句：only+状语置于句首，后面的句子用部分倒装，句意：只有当他期末考试失败，他才下决心更努力学校，赶上其他同学。说明用的是过去时，选D。