Tom his homework yesterday because he was in hospital all day.A. can’t finishB. couldn’t

问题补充：

Tom his homework yesterday, because he was in hospital all day.

A. can’t finish

B. couldn’t finish

C. couldn’t have finished

D. mustn’t finish

答案：

A. can’t finish

B. couldn’t finish

(答案→)C. couldn’t have finished

D. mustn’t finish

解析：考查情态动词表示推测。根据第二句的过去时，说明是对过去的推测，使用“情态动词+have done”对过去的情况进行推测。如果是对现在情况的推测，使用“情态动词+动词原形”；句意：Tom不可能完成他的家庭作业，因为他整体都住院。故C正确。