信用保险的一个特点是（）。 A.信用产生较早 B.投保人都是权利人 C.把债务人的保

If you feel tired out and unable to think clearly,that is________you have to get a rest.[ ]

A. why  

B. when  

C. whether  

D. what

政策执行的基本手段主要包括哪些？（）

A、行政手段

B、法律手段

C、经济手段

D、思想控制手段

E、思想引导手段

1874年，由德国学者提出的一种将全数的变量值固定在报告期，以此计算一组项目的综合指数的指数计算方法是______。

A．拉氏指数B．帕氏指数C．综合指数D．个体指数

(51) is a six bytes OSI layer 2 address which is burned into every networking device that provides its unique identity for point to point communication.

(52) is a professional organization of individuals in multiple professions which focuses on effort on lower-layer protocols.

(53) functions with two layers of protocols. It can connect networks of different speeds and can be adapted to an environment as it expands.

(54) is the popular LAN developed under the direction of the IEEE802.5.

(55) is the popular backbone technology for transmitting information at high speed with a high level of fault tolerance which is developed under the direction of ANSI.

（52）是（）

A.ISO

B.ANSI

C.CCIT

D.IEEE

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