一般情况下，主要影响舒张压高低的是（）
A.每搏量
B.心率
C.外周阻力
D.大动脉弹性
E.循环血量/血管容量比例
参考答案：C
A．the high pay makes her feel obliged to do it
B．she was required by the contract to do it
C．she wants to experience the real life of the character
D．it was fun to do it
制冷系统排污时，适合使用的气体是（）。
A.氧气
B.压缩空气
C.氢气
D.乙炔气
