网络中的信息安全保密主要涉及两个环节，即信息的存储和信息的
A．伪造
B．传输
C．窃听
D．截获
参考答案：B
—What are you mailing, Tom?
— A textbook a new method of teaching physics. I want my friends to take a look at it.
A．is based on
B．based on
C．basing upon
D．which based upon
防烟方式分为机械加压送风方式或自然通风方式。（）
