题目

 But for the fact that China _________ also affected by the global economic crisis, we _________ fewer unemployed workers now. A. is; would have                       B. were; would have  C. was; would have had                  D. were; would have had 答案：A 青藏铁路已全线贯通，已经投入运营的高原列车有完善的供氧系统和完备的医疗应急系统，这样做主要是因为 [　　] A．高原空气稀薄，大气压强小 B．高原空气稀薄，大气压强大 C．高原空气稠密，大气压强小 D．高原空气稠密，大气压强大