单选题 She looks tired. She ______ last night.
A. should have stayed up late B. must have stayed up late
C. need have stayed up late D. would have stayed up late

【正确答案】 B

【答案解析】[解析] 语法分析题。情态动词完成式。根据题意和句子逻辑关系，这里表达一种对过去事情的推测，故B为正确答案。句意：她看起来很累，昨晚她一定熬夜了。