柴油发动机供给系由空气供给装置、燃料供给装置、混合器形成装置及（）组成。
参考答案：废气排出装置
健康者进入高原地区发生缺氧的主要原因是
A．吸入气氧分压低
B．肺换气功能障碍
C．肺循环血流量少
D．血液携氧能力低
E．组织血流量少
Mary as well as her sisters ___ Chinese in China. [ ]
A. are studying
B. have studied
C. is studying
