—You don’t look well． Are you ill?
—No, the mid-term exam is ing and I reading until midnight．
A. stayed up
B. am staying up
C. have stayed up
D. will stay up
网友回答
(答案→)A. stayed up
B. am staying up
C. have stayed up
D. will stay up
解析：句意：--你看起来脸色不好，你生病了吗？--没有，期中考试快到了我熬夜看书学习到深夜。根据这个对话可以看出熬夜带来的结果是脸色不好，所以熬夜肯定已经发生了。故选A。