SF6气体常用的吸附剂有()。
A.活性氧化铝和分子筛
B.氧化硅
C.硅胶
D.硫酸白土
参考答案:A
出现跨瓣压差时二尖瓣狭窄面积在()
A.1.5~2.0cm4
B.≤2.0cm2
C.≤1.5cm2
D.≤1.0cm2
E.2.0~2.5cm2
汉译英:“一式两份;一式三份;一式四份”,正确的翻译为:()
A.in duplicate; in quadruplicate; in triplicate
B.in quadruplicate; in triplicate; in duplicate
C.in triplicate; in duplicate; in quadruplicate
D.in duplicate; in triplicate; in quadruplicate