问题 填空题

下表为一个路由器的路由表。如果该路由器接收到一个源IP地址为10.0.0.10、目的IP地址为40.0.0.40的IP数据报,那么它将把此IP数据报投递到______。

要到达的网络下一路由器
20.0.0.0直接投递
30.0.0.0直接投递
10.0.0.020.0.0.5
40.0.0.030.0.0.7

答案

参考答案:30.0.0.7

解析: 在因特网中,需要进行路由选择的设备一般采用表驱动的路由选择算法。每台需要路由选择的设备保存一张IP选路表(路由表),需要传送IP数据报时,它就查询该表,决定把数据报发往何处。一个路由表通常包含许多(N,R)对序偶,其中N指的是目的网络的IP地址,R是到网络N路径上的“下一个”路由器的IP地址。

阅读理解

D

Do you know what a castle is? A castle is a building special to Europe. Castles were built in the Middle Ages by king and other powerful people who live in. Castles were used by people to protect themselves from their enemies. They are big buildings made form stone and wood.

Today there are still castles all over Europe. Some are in ruins(废墟). But some built later are still in good repair and used even today. One example is Windsor Castle, which is a home to the British queen. It is in the country or Berkshire, not far from London.

Castles have walls around them. In the old days, soldiers would stand on the walls to guard the people in the castle. If enemies came they would shoot arrows(箭) and throw stones at them. Castles also had moats. A moat is a river around the wall that makes it difficult for enemies to get in. It could be either dry or filled with water.

Other people form younger countries love European castles. In the US there are rich people who have brought broken parts of castles to their country and rebuilt them. And some people build “replica” castles---modern copies of Castle.

You probably know the Disneyland Castle in California , US. But did you know it is based on a famous castle in Germany built by King Ludwig Ⅱof Bavaria?

小题1: Which of the following is TRUE about the castle?

A.It is a special American building.

B.It is made form stone and paper.

C.Only king used to live in one.

D.People used it to protect themselves.小题2: We can tell from the story that a moat is __________.

A.a wall

B.a soldier

C.a river

D.a stone小题3:According to the passage we can know that______________.

A.There are castles only in some European countries now.

B.In the US, there used to be castles in the Middle Ages.

C.In the US, the people rebuilt the old castles or build the modern ones.

D.The Disneyland castle is built in Germany.小题4: What does the passage mainly talk about?

A.The history of castles.

B.Facts about castles.

C.The king and the castles.

D.How to build castles.

问答题 论述题