单选题 Questions 57 to 61 are based on the following passage.
All carbon footprints are hard or impossible to pin down accurately, but the Internet is a particularly complex case.
It's possible, nonetheless, to take a rough stab at working out the Internet's carbon footprint. A good place to start is the world's data centres--buildings packed top to bottom with servers full of the web pages, databases, online applications and downloadable files that make the modern online experience possible. Data centres use lots of electricity, both for powering the machines they contain and--all importantly--for the air conditioning needed to keep the servers from overheating.
According to a report by Gartner, data centres already account for around a quarter of the energy consumed (and the carbon emitted)by the information and communication technology (ICT)sector as a whole. In other words, around half a percent of global CO2 emissions.
These figures tie in fairly well with a study by the UK's market transformation program, which concluded that 343. 5 million tonnes of CO₂ was down to consumer and commercial ICT in 2005-- equivalent to around 1.2% of current fossil-fuel CO₂ emissions. ICT's footprint is due to climb by 60% by 2030, the same report suggests. If that was to happen, and global emissions had already fallen by then, as climate change experts suggest they must, then the internet's share of total carbon output would climb significantly higher still.
All this depends on what happens between now and then, of course. Companies have already been exploring technologies that can take the heat from data centres and use them to warm nearby buildings, thereby reducing internal air-conditioning requirements and local demand for heating fuels.
In the meantime, it's interesting to note that 1% is about the same proportion as printing and paper-based publishing represents in the UK. The comparison isn't entirely valid, for a whole host of reasons, but the fact remains that despite ecological claims for the virtual economy, the digital era may be no less energy-hungry than the paper-based world of 20 years ago. Part of the reason is the so-called rebound effect--the phenomenon that when something (in this case the storing and interrogation of data)becomes cheaper and more energy-efficient, we often end up simply doing more of it, with the result that there is no net reduction, or even a rise, in cost or impact.
On the other hand, the internet is likely to be crucial to any move to a low-carbon world. Without its capacity to carry the huge flows of energy data, there could be no "smart grid", for example, and without online video conferencing it would be much harder to reduce the number of business flights in coming years. Ultimately, then, it's not just technological developments that will affect the growing carbon footprint of the Internet. Just as important is how we choose to use it.

单选题 Why do data centers consume so much electricity?

A. Much electricity makes the online experience possible.
B. Data centers are equipped with numerous electronic devices.
C. Data centers are tall buildings packed from top to bottom with severs.
D. The machines and air conditioning system consume much electricity.

【正确答案】 D

【答案解析】[解析] 根据题干关键词data centers，electricity定位到原文第二段最后一句：Data centres use lots of electricity, both for powering the machines they contain and--all importantly--for the air conditioning needed to keep the servers from overheating. 可知数据中心要消耗大量的电能，这些电能用于维持机器的运转和一很重要的一用于防止服务器过热的空调系统的工作。故选D)项。 [避错点拨] A)项“大量电能使各种网上行为成为可能”与B)项“数据中心建筑里有无数电子装置”只是部分原因；C)项“数据中心建筑里全是服务器”原文有提及，但不是具体原因。

单选题 What would happen if ICT's footprint were to climb by 60% by 2030?

A. Global CO₂ emissions would decline greatly.
B. Climate change would be much fiercer than before.
C. Carbon output share caused by the Internet would soar.
D. Global temperature would climb to a new height.

【正确答案】 C

【答案解析】[解析] 根据题干关键词ICT's footprint，by 60% by 2030定位到原文第四段最后两句：ICT's footprint is due to climb by 60% by 2030, …experts suggest they must, then the internet's share of total carbon output would climb significantly higher still. 可知这份报告同时也认为，ICT的碳足迹到2030年将上升60%，如果这种情况发生，并且到那时全球碳排放已经下降——气候变化专家认为它们肯定会下降，那么互联网在总的碳排放中所占的比例依然会显著升高。故选C)项。 [避错点拨] A)项“全球二氧化碳排放将大幅下降”是对原文的曲解，文中只提到会下降；B)项“气候变化将比以前更为剧烈”与D)项“全球温度将创新高”文中未提及。

单选题 What's the possible way for data centers to reduce carbon footprints?

A. Energy-efficient technologies should be adopted.
B. Air-conditioning system should be improved.
C. The heat from data centers can be recycled.
D. Heating fuels should be used less in local areas.

【正确答案】 C

【答案解析】[解析] 根据题干关键词data centers定位到原文第五段第二句：Companies have already been exploring technologies that can take the heat from data centers and use them to warm nearby buildings, thereby reducing internal air-conditioning requirements and local demand for heating fuels. 可知很多公司正在寻找新的技术，希望能够把数据中心的热量转移出来为附近的建筑供暖，这样就会降低对室内空调的要求和当地对供暖燃料的需求。故选C)项。 [避错点拨] A)项“应采用高能效的技术”文中未提及；B)项“改进空调系统”与D)项“当地应减少燃油的使用”是对原文的曲解。

单选题 What may rebound effect lead to?

A. Energy-efficiency.
B. Net reduction.
C. Higher cost.
D. Less impact.

【正确答案】 C

【答案解析】[解析] 根据题干关键词rebound effect定位到原文第六段最后一句：Part of the reason is the so-called rebound effect…with the result that there is no net reduction, or even a rise, in cost or impact. 可知当某些东西变得更便宜和更节省能源时，我们通常只会做更多这样的事，而事实却是能量需求并没有降低，甚至在成本或对环境的影响上还有所上升。故选C)项。 [避错点拨] A)项“高能效”B)项“净减少”D)项“较少影响”均是对原文的曲解。

单选题 What do we learn from the last paragraph?

A. Technologies lead to the increased carbon footprint of the Internet most.
B. The Internet is the only effective means to achieve low-carbon world.
C. Online video conferencing is the only way to reduce business flights.
D. People's usage of technology is equally important as technologies themselves.

【正确答案】 D

【答案解析】[解析] 根据题干定位到原文最后：it's not just technological developments that will affect the growing carbon footprint of the Internet. Just as important is how we choose to use it. 可知不仅仅是技术发展造成了互联网与日俱增的碳排放，我们的选择和使用也是重要因素。故选D)项。 [避错点拨] A)项“技术是导致二氧化碳排放升高的主要原因”B)项“互联网是实现低碳生活的唯一有效途径”C)项“网上视频会议是减少商务飞行的唯一办法”均是对原文的曲解。