蒸气系统的减压阀组前，应设（）。
A.疏水器
B.汽水分离器
C.导淋阀
D.安全阀
参考答案：A, B
--- People should stop using their cars and start using public transport．
--- _______．The roads are too crowded as it is．
A．All right
B．Exactly
C．Go ahead
D．Fine
呼气性呼吸困难见于（）
A.支气管哮喘
B.气管异物
C.气管肿瘤
D.喉头水肿
E.白喉
