单选题 Recently he ______ every night until after one o'clock, preparing for the final exam.
A. shows up B. show off C. stays in D. stays up

【正确答案】 D

【答案解析】[考点] 动词词组词义辨析
[解析] show up意为“揭露，露出，露面”；show off意为“炫耀，显耀”；stay in意为“在家，不外出”；stay up意为“熬夜，不睡觉”。根据句意，故选D。