题目

Why does the woman look unhappy?A.She has to work overtime. B.She can’t go to the movies. C.She doesn’t feel well. 答案：【答案】C【解析】【原文】M: Oh, why do you still have the long face? I don’t want to work overtime, either. I promise I’ll go to the movies with you next time, okay?W: No, it’s not like that. My belly… Excuse me, but I have to use the toilet now.15．如图，在三棱柱ABC-A1B1C1中，侧面AA1C1C⊥底面ABC，AA1=A1C=AC=2，AB=BC，且AB⊥BC，O为AC中点，则直线A1C与平面A1AB所成角的正弦值为（　　）A．$\frac{3}{5}$B．$\frac{\sqrt{21}}{7}$C．$\frac{1}{2}$D．$\frac{\sqrt{3}}{2}$