you come to my birthday party tomorrow Robert? --I’m afraid not. I have to study for

问题补充：

-- you come to my birthday party tomorrow, Robert?

--I’m afraid not. I have to study for my exam.

A. Must

B. Should

C. Can

D. Need

答案：

A. Must

B. Should

(答案→)C. Can

D. Need

解析：考查情态动词，Must 必须，Should 应该，Can 能，会，Need 需要，句意：罗伯特，你明天能来参加我的生日聚会吗？恐怕不行，为了考试我要学习。所以选C。