调经的具体原则是（） A.调经以治本 B.病在气者，当以治气为主，佐以养血活血 C.

—Did your father _____ catch a cold?

—No,  he didn't. But he _____ the weather here.          [ ]

A. often,  used to

B. never,  be used to

C. often,  was used to

There was a fire in the hotel around midnight last Friday. Luckily, it was soon          .

A．turned on

B．turned off

C．put on

D．put out

呼吸道对进入的气体有______、______和______作用．

下列防护用品中，安全带和安全绳属于哪一类防护用具？

A.呼吸护具 

B.眼防护具 

C.防坠落护具

心力衰竭的常见诱因是以下哪些情况。（）

A.呼吸道感染

B.心房纤颤

C.洋地黄中毒

D.钠盐摄入过多

E.静脉输入液体量过少