压力式除氧器应采用全启式弹簧安全阀，且不少于（）只。
A.1
B.2
C.3
参考答案：B
---What do you think of MoYan?
----In my opinion, he is the other famous.
A． as great a writer as
B．great as a writer as
C． a writer so great as
D．as a great writer as
哪项不是诱发静脉导管感染的常见因素（）
A.经创面静脉置管
B.静脉内输入高价营养
C.静脉内置管长于7天
D.经中心静脉置管
E.经周围静脉置管
