(2013·四川高考)—Why are your eyes so red? You have slept well last night.
—Yeah, I stayed up late writing a report.
A. can't
B. mustn't
C. needn't
D. won't
网友回答
(答案→)A. can't
B. mustn't
C. needn't
D. won't
解析：A 考查情态动词的用法。句意：“你的眼睛为什么那么红啊？昨晚你不可能睡得很好。”“是的，我熬到很晚写一篇报告。”can't have done指过去不可能做……。