—Why do you look tired?—Because I until 11:50 last night.A. stayed upB. stayed awayC. stay

问题补充：

—Why do you look tired?—Because I until 11:50 last night.

A. stayed up

B. stayed away

C. stayed at

D. stay in

答案：

(答案→)A. stayed up

B. stayed away

C. stayed at

D. stay in

解析：stayed up不睡觉，熬夜；stayed away外出，远离；stayed at暂住在……，保留；stay in呆在家，不外出。句意：你为什么看起来很累？——因为昨晚我熬夜到11:50.结合语境可知选A。