U衰变为Rn要经过m次a衰变和n次b衰变，则m，n分别为（） A．2，4 B．4

—Why don't we hold a party to celebrate the achievements gained by our players?

—________[ ]

A. Because we haven't got enough preparations.

B. Good idea!

C. It's all because of the terrible weather.

D. Not all would like to attend it.

使用人工呼吸机时，应调节吸气与呼气的比为

A．1:(1．5～3)

B．2:1

C．(1．5～2):1

D．1:1

E．2:(1．5～3)

体重达出生体重3倍的年龄是

A．原发型肺结核

B．浸润型肺结核

C．血行播散型肺结核

D．慢性纤维空洞型肺结核

E．结核性胸膜炎

下列哪项属于循环系统的不良反应（）

A.气短

B.水肿

C.困倦

D.腹泻

E.皮疹