Everyday rubbish could provide a valuable source of energy thanks to a clever new invention. Smelly methane（沼气）gas expelled from landfill sites containing tones of rotting household waste could be used to produce a valuable energy resource. In Europe alone land fill tips produce 94 billion cubic meters of methane per year but currently only one percent of what could be a valuable source of energy is used, the rest is burnt off to prevent an explosive build up of gas.
Methane gas forms when organic matter breaks down and is drawn off from large rubbish tips by pipes sunk into the middle of the waste. Until now this process wasn’t possible on small sites because the pipe allowed oxygen to seep in and that stop the breakdown process.
Viktor Popov of the Wessex Institute of Technology has now developed a system to modify existing landfill sites by making them airtight while the methane is extracted from sunken wells. The site is covered by a special three-layered skin whose two outer layers are made of clay with a pressurized（加压的）layer of carbon dioxide gas in the middle. As the methane is sucked out through a central well it is replaced by carbon dioxide from the middle layer rather than oxygen, allowing the breakdown process to continue.
Unfortunately there are no plans to use the power of methane even though Popov claims his invention could provide a valuable source of energy over the next 20 years.
【小题1】The passage mainly introduces to us.A．how to make methaneB．a new way to make use of rubbishC．the valuable things in rubbishD．the amount of rubbish beig reused【小题2】From the passage we can see that .A．in Europe 94 billion cubic meters of methane is produced every yearB．some of the waste will explode if it is not burnt offC．99% of the rubbish has been burnt off in EuropeD．only a very small part of this kind of energy is used in Europe【小题3】In the passage the underlined word “that” refers to .A．methane gasB．the long pipeC．oxygenD．the rubbish【小题4】Which of the following statement is NOT true according to the passage?A．Oxygen can cause the breakdown process to stop.B．When the methane is sucked out, oxygen will enter from the middle layer.C．Carbon dioxide doesn’t affect the breakdown process.D．The new invention has not been put into use.B
网友回答
(答案→)B
解析：
【小题1】整篇文章介绍了一种新发明——利用生活垃圾生产沼气。
【小题2】从第一段第三句可以看出，仅欧洲本身的垃圾每年就能生产出94亿立方米的沼气，但
只有1%得到利用，其余全部烧毁以防气体爆炸。
【小题3】根据前面的“管道让氧气渗入”判断that指的是“氧气”。
【小题4】从倒数第二段可知，当沼气通过中井被吸出来后，来自中间层的二氧化碳会取而代之，而非氧气。