问题 单项选择题

下列关于路由表的描述中,错误的是()

A.网络结构变化时,静态路由表无法自动更新

B.动态路由表由系统自动运行动态路由选择协议,可以自动更新结构

C.静态路由表一般只用在小型的、结构不会经常改变的局域网系统中

D.动态路由表通常用于结构经常改变的网络,或者是故障查找的试验网络中

答案

参考答案:D

阅读理解

阅读理解。

     A volcanic eruption in Iceland has sent ash across northern Europe. Airlines have stopped or changed the

flights across the Atlantic Ocean, leaving hundreds of passengers stuck in airports.

     Grirmsvom is one of the largest and most active volcanoes in Europe. What makes Grimsvom different

is that it lies under a huge glacier (冰川) of ice up to 12 maters thick. The hot volcano heats up the ice above

it, which then forms a layer (层) of water between the glacier and the volcano. This layer of water puts

pressure on the volcano, keeping it stable. As the water flows out from under the glacier, the pressure lifts.

The lava (岩浆) from the volcano then comes up to the surface. This is exactly what happened today.

     Now, airlines have to make changes to their flights so as not to fly through the clouds of volcanic ash.

According to KLM. one of Europe's biggest airlines, airplanes cannot go under the cloud or over it. Going

through the cloud can result in ash getting stuck in the airplane's engines, causing damage to the plane.

     The eruption has also caused problems for animals in Iceland. The volcano left ash and sharp. Glass-like

rocks all over the countryside. Farmers are keeping their animals inside to stop them from eating ash-covered

grass to the sharp object.

1. What makes Grimsvom different from other volcanoes?

A. It is below ice

B. It lies under the sea

C. It is the largest volcano

D. It is lava affects the airlines

2. What keeps Grimsvotn still?

A. The slow flow of water

B. The low water temperature

C. The thick glacier

D. The water pressure

3. Which of the following is the result of the volcanic eruption?

A. People stop traveling in Europe

B. Airlines suffer from the loss of planes

C. It becomes dangerous for animals to eat outside

D. Farmers have lost many of their animals

4. This text is most probably taken from _____. 

A. a research paper

B. a newspaper report

C. a class presentation

D. a geography textbook.

单项选择题