In order to finish the research, the professor always , for every day the light in hisroom didn’t go out until 4 a.m.
A. mixed up
B. cleaned up
C. turned up
D. stayed up
网友回答
A. mixed up
B. cleaned up
C. turned up
(答案→)D. stayed up
解析：词义辨析题。A. mixed up 混合 B. cleaned up 清理 C. turned up 出现 D. stayed up 熬夜 为了完成研究教授总是熬夜因为每天他的房间的灯都会亮到凌晨四点。 选D