—Sorry indeed. I to your birthday party if …—Forget it. I know you were out on business.A.

问题补充：

—Sorry indeed. I to your birthday party if …

—Forget it. I know you were out on business.

A. must come

B. would come

C. must have come

D. would have come

答案：

A. must come

B. would come

C. must have come

(答案→)D. would have come

解析：

这题考查虚拟语气的用法，从上下文看，说话人是没能参加生日聚会，所以用would have done，“本可以做却没做”。句意是：--真是抱歉，如果..我本可以去参加你的生日聚会的，--没事，我知道你在外做生意的。选D。