you were coming I would have stayed at home.A. If I knowB. Should I knowC. Had I knownD. I

问题补充：

you were coming，I would have stayed at home.

A. If I know

B. Should I know

C. Had I known

D. If I should have known

答案：

A. If I know

B. Should I know

(答案→)C. Had I known

D. If I should have known

解析：句意：我要是知道你要来，我就呆在家里了。根据I would have stayed at home.可知是和过去相反的虚拟语气，从句用过去完成时，这里可以省略if，将had提前，所以选C。