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问题 选择题

我们生活在千姿百态的物质世界里，各种物质之间存在着多种相互作用，也不断发生着变化。下列生活中的常见变化中，只有物理变化的是 [ ]

A．纸张燃烧

B．冰雪融化

C．食物腐烂

D．铁钉生锈

答案

答案：B

单项选择题

计算机辅助教学简称（），是指用计算机帮助或代替教室执行部分或全部教学任务，传递教学信息，对学生传授知识和训练技能，直接为学生服务。

A.CMI

B.CAI

C.CAM

D.CBE
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单项选择题

(66) is a one-way function that takes an arbitrarily long piece of plaintext and from it computes a fixed,length bit string. (67) is a protocol that most USENET machines now use it to allow news articles to propagate from one machine to another over a reliable connection. (68) is an approach preferred by cable TV providers. In this solution the fiber terminates at an opt~electrical converter and the final segment is a shared coaxial cable. (69) is a device used to connect two separate network that use different communication protocol. (70) is a digital-to-digital polar encoding method in which the signal level is always either positive or negative.

A．MD

B．RSA

C．DES

D．MIB
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