未分类题

根据下面的文字资料回答 4～8 题 在OSI参考模型中，物理层的功能是（ 1 ）等。实体在一次交互作用中传送的信息单位称为（ 2 ），它包括（ 3 ）两部分。上下邻层实体之间的接口称为服务访问点(SAP)，网络层的服务访问点也称为（ 4 ）)，通常分为（ 5 ）两部分。
第4题：文中（ 1 ）处正确的答案是（ ）。

A.建立和释放连接
B．透明地传输比特流
C．在物理实体间传送数据帧
D．发送和接收用户数据

【参考答案】

B
0SI指开放网际互连，它共分为7层结构。分别是：
·应用层：提供网络访问的用户接口。......

(↓↓↓ 点击下方‘点击查看答案’看完整答案 ↓↓↓)
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Jungle country is not friendly to man, but it is possible to survive there. You must have the right【21】and you must know a few important things about the jungle. Then your chances of staying【22】are very good. In the jungle, you should always carry a【23】. Then you can【24】which way to go. Again and again you must check your position by it. Keep alert. Watch the ground in front of you carefully. Stop and listen【25】. If you lose your【26】, do not be afraid. Mark the spot where you are with blazes on a tree. Then you can always know where you started. Finding water that is safe to drink can be a problem. Many streams and rivers carry germs that can be【27】to man. Luckily, the jungle has many kinds of plants and vines that give water.【28】in the jungle is a science. Learn as much as you can about what to【29】in the jungle. Then no part of the jungle will seem completely unfriendly or frightening. In fact, you will be able to '【30】' it for a long time.(36)A．adviceB．partnerC．toolD．equipment
A.
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【28】in
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(36)
A．advice
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根据下面的文字资料回答 2～3 题在双绞线布线后要进行测试，一般情况，下面（ 1 ）不是测试的项目。光纤测试的内容不包括（ 2 ）项目。 第2题：文中（ 1 ）处正确的答案是（ ）。
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