关于气相法生产过程中发生反应器温度上升异常，下列可能的原因有（）.A、急冷液泵故障

—Look at the flowers I gave you last month. They are dying! ________ do you water them?

—Sorry, I forgot to water them.

A．How long

B．How often

C．How soon

D．How much

诱发肺源性心脏病功能失代偿的最常见原因是（）。

A.过度劳累

B.补液过快

C.呼吸道感染

D.摄盐过多

E.心律失常

After graduation from college, he began to wander from city to city, ________a suitable job. [ ]

A. hunting for  

B. taking on

C. looking after  

D. bringing up

徐州火车站的规模在全国来讲都是属于特级的，请问它在全国排第几？

(1) is used to ensure the confidentiality, integrity and authenticity of the two end points in the private network. (2) , an application-layer protocol, authenticates each peer in an IPsec transaction. IKE negotiates security policy, determining which algorithm may be used to set up the tunnel. It also handles the exchange of session keys used for that one transaction.

Networks that use (3) to secure data traffic can automatically authenticate devices by using (4) , which verify the identities of the two users who are sending information back and forth. IPsec can be ideal way to secure data in large networks that require secure connections among many devices.

Users deploying IPsec can (5) their network infrastructure without affecting the applications on individual computer. The protocol suite is available as a software-only upgrade to the network infrastructure. This alows security to be implemented without costly changes to each computer. Most important, IPsec allows interoperability among different network devices, PCs and other computing systems.

3（）

A．authenticity

B．IPSec

C．confidentiality

D．integrity