问题 单项选择题

虚拟网络以软件方式来实现逻辑工作组的划分与管理。如果同一逻辑工作组的成员之间希望进行通信,那么它们

A.可以处于不同的物理网段,而且可以使用不同的操作系统

B.可以处于不同的物理网段,但必须使用相同的操作系统

C.必须处于相同的物理网段,但可以使用不同的操作系统

D.必须处于相同的物理网段,而且必须使用相同的操作系统

答案

参考答案:A

解析:虚拟网络中同一逻辑工作组的成员可以处于不同的物理网段,而且虚拟网络与操作系统无关。

单项选择题
阅读理解

阅读理解。

     Have you dreamed of building your own machine? Do you wish you could invent something new? Here we look at a few British inventions of recent times.

Adaptive glasses

     Do you wear glasses? If so, can you imagine life without them? In 1985, Joshua Silver, a professor at   Oxford University, asked himself, "Can I invent a pair of glasses that could be changed

by the wearer?" He designed two plastic lenses (透镜) that are filled with a special liquid. Using

syringes (注射器) you change the liquid between the lenses until you can see clearly. The glasses are

not beautiful but they are easy to use and cheap to make.

     The wind-up radio

     When you switch your  TV on tonight, think about all those people without electricity. Thinking about

this, Trevor Baylis came up with the idea of designing a radio that could be powered by hand. In common with Joshua Silver he wanted his invention to be cheap and easy to use. He wanted even the poorest

people in developing countries, who don't have electricity and cannot afford batteries, to use it. The radio

has a generator(发电机)which is powered by turning a handle. In 1996 it won the BBC Design Award for Best Product and Best Design.

     The Dyson vacuum(真空) cleaner

     In many homes around the world you can see a cleaner that looks like a spaceship. This is the Dyson

vacuum cleaner which uses something called "cyclonic separation" to separate the dirt. You do not need

a bag for your cleaner and it does not get blocked so it is very practical. The idea came to Sir James

Dyson after he kept having problems with his vacuum cleaner. He decided he could design a better one

and in 1993 he opened his own factory. The Dyson is now one of the best-selling cleaners in the UK and Dyson is believed to have earned over a billion pounds.

     The Zapata flyboard

     Have you ever dreamed of zooming through the water and leaping in the air like a dolphin? Now you

can, thanks to a flyboard, built by water sports enthusiast Frank Zapata. With it you can dive back in the

water  and out again. It's possible to jump to incredible heights out of the water-over 30 feet. The basic

flyboard model comes in at £4,200.

     So keep dreaming and inventing. One day you might get it right.

1. Which might be the best title for the passage?

A. Greatest Inventions

B. Scientists' Stories

C. Magic Glasses

D. Beautiful Minds

2. What can we learn about adaptive glasses?

A. They are very expensive.

B. The inventor is a student

C. The glasses are fragile.

D. They don't look very nice.

3. Which invention won an award?

A. Adaptive glasses.

B. The wind-up radio.

C. They Dyson vacuum cleaner

D. The Zapata flyboard.

4. The Dyson vacuum cleaner was invented with the purpose of .

A. helping people use cleaners easily

B. making Dyson a rich businessman

C. keeping the house cleaner than before

D. taking the place of human cleaners