He hadn’t worked hard at his lessons he failed in the exam．A. As a resultB. HoweverC. Ot

问题补充：

He hadn’t worked hard at his lessons．, he failed in the exam．

A. As a result

B. However

C. Otherwise

D. Since then

答案：

(答案→)A. As a result

B. However

C. Otherwise

D. Since then

解析：句意：他不努力学习功课。结果，考试失败了。前后存在着逻辑上的因果关系；故选A。