It’s too bad that I failed in the math exam. If only I hard at it!A. workedB. had worked

问题补充：

It’s too bad that I failed in the math exam. If only I hard at it!

A. worked

B. had worked

C. has worked

D. would work

答案：

A. worked

(答案→)B. had worked

C. has worked

D. would work

解析：考查虚拟语气：if only表示“但愿…就好了”，后面的从句用虚拟语气，谓语用相应的过去时，和现在相反用过去时，和过去相反用过去完成时，和将来相反用过去将来时。这句话是指和过去相反，用过去完成时。句意是：我数学考试没及格，真是太糟糕了。选B