运动时心输出量增加的原因有（）
A.心率增快
B.心肌收缩能力增强
C.回心血量增加
D.前负荷增加
E.后负荷增加
参考答案：A, B, C, D
A series of stimulus policies and supportive measures taken by the government ________ to promote
change in the economic environment in this area. [ ]
A. is expected
B. are expected
C. is expecting
D. are expecting
肺性脑病不能用高浓度吸氧，主要是因为
A．促使CO2排出过速
B．可引起氧中毒
C．诱发代谢性酸中毒
D．缺氧纠正后解除了主动脉体和颈动脉体的兴奋性
E．缺氧不是主要因素
