客运专线在双线地段，单轨小车应面向来车方向在（）上推行。
参考答案：外股钢轨
You _ so cute then, but now you naughty. [ ]
A. are; are
B. were; were
C. were; are
鼻导管低流量(3L／min)给氧，FiO2可达（）
A.24%
B.28%
C.32%
D.36%
E.40%
