问题 问答题 简答题

工作面过断层时怎样进行回柱放顶?

答案

参考答案:

工作面过断层时顶板都比较破碎,回柱时一般情况下是随回随落,有时回一根柱留下来的矸石可能埋几根没回撤的支柱。一般的办法用木柱替换金属支柱,再回撤木柱。在开始回柱前先将断层处每个顶梁下支一根木柱,按先切顶支柱后支架的顺序回撤。当回撤3~4m后,再回撤木支柱,将回撤的坑木继续支在前方的顶梁下,使木支柱与回柱间的距离保持3~4m。为防止漏矸可用长短不一笆片或笆捆挡矸。

阅读理解

阅读理解。

     Cell phones are all around us. We use cell phones to call our friends, send text messages, play

games, and even take photographs. Now imagine using your cell phone to call your air conditioner. If

this were possible, you could tell your air conditioner to turn on before you got home. Does this sound

impossible to you? Well, it could become possible sooner than you think. In the near future, we might

use cell phones as remote controls for the electrical devices in our homes.

     People are already working to develop different ways to communicate wirelessly with devices we

use every day. For example, it is already possible for cell phones to communicate with laptop

computers. Business people using laptops during meetings can use their cell phones as remote controls.

They can use their cell phones to send instructions to computers to turn on, change pictures, and turn

off.

     With the same technology, people can use their cell phones to control other devices. You can call

your stereo to play music automatically. You can call your lights to turn on when you enter a room.

Maybe even by next summer you will be able to call your air conditioner!

1. What is the main idea of this passage?

A. In the future we will all need air conditioners.

B. Business people need to use computers.

C. Some people like to make phone calls to machines.

D. We will use cell phones as remote controls in the future.

2. Cell phones can be used to turn on and off ________ in the future.

A. a special computer

B. different kinds of devices

C. cell phone companies

D. remote controls

3. Which probably could NOT be controlled by a cell phone?

A. An air conditioner or heater.

B. A computer or printer.

C. A table or a basket.

D. A CD player or MP3 player.

4. When will people be able to use their cell phones as remote controls for their homes?

A. Now.

B. Soon.

C. In ten or fifteen years.

D. Never.

5. Which instructions can be sent to a laptop according to the passage?

A. Play sound and music.

B. Start and shut down.

C. Call again and hang up.

D. Go faster and go slower.

单项选择题 A1/A2型题