储存0℃以下介质的压力容器,应选用()液位计。
A、浮子式
B、玻璃管式
C、防霜
D、防爆
参考答案:C
Firewall is a()mechanism used by organizations to protect their LANs from the Internet.
A.reliable
B.stable
C.peaceful
D.security
侧面上的圆的斜二测投影仍然为圆。