A
Solar energy collection faces no shortage of problems.Scientists have discovered another block(阻碍)：air pollution.In certain parts of the globe，its influence on solar panels(太阳能面板) can decrease energy output by more than 25 percent，according to a new study.
“My colleagues in India were showing off some of their rooftop solar installations，and I was blown away by the panels and couldn't describe how dirty they were，” said Michael Bergin，a professor of environmental engineering at Duke University and lead author of the study.“I thought the dirt must affect their efficiency，so we put together a model to do just that.”
Working with his colleagues at the Indian Institute of TechnologyGandhinagar，Bergin measured the efficiency of the school's solar panels as they became dirty over several months.The chemical analysis showed that 92 percent of the dirt was natural dust.The remaining 8 percent pollutants came from human activities，such as fossilfuel and biomass combustion (生物质燃烧)．Although this latter group contributed to a smaller percentage of the overall dirt on the solar panels，it can result in greater energy loss，Bergin said.
The manmade pollutants are small and sticky(粘的)，making them much more difficult to clean off.In addition，smaller pollutants block sunlight more efficiently than natural dust does.Although cleaning the panels produced an immediate 50 percent increase in energy gathering，Bergin warned against it.“The more you clean them，the higher your risk of damaging them，” he said.
“We always knew these pollutants were bad for human health and climate change，but now we've shown how bad they are for solar energy as well，”Bergin added.“It's yet another reason for policymakers worldwide to adopt emission controls.”
【语篇解读】 本文介绍了影响太阳能收集的一个容易被忽略的因素：空气污染，尤其是人类活动造成的颗粒污染，其中所占比例虽小但影响巨大。
1．What does the underlined part in Paragraph 2 mean?
A．Touched. B．Shocked.
C．Shamed. D．Changed.
解析：词义猜测题。根据第二段“couldn't describe how dirty they were”可推断，迈克尔·伯金觉得太阳能面板很脏，这让他感到震惊。
答案：B
2．According to Paragraph 3，solar panels________．
A．should always be used in clean areas
B．are mainly polluted by human activities
C．can stop work when natural dust gathers
D．work inefficiently with manmade pollutants
解析：细节理解题。根据第三段“Although this latter group contributed a smaller...can result in greater energy loss”可知，人类污染物会严重降低太阳能面板收集太阳能的效率。
答案：D
3．What can we infer from Paragraph 4?
A．There's no need to clean off natural dust.
B．People should replace solar panels frequently.
C．Solar panels shouldn't be cleaned frequently.
D．Manmade pollutants are heavier than natural dust.
解析：推理判断题。根据第四段“Although cleaning the panels produced...The more you clean them，the higher your risk of damaging them”可知，太阳能面板极易因为清洁而受损，即太阳能面板并不适合频繁清洁。
答案：C
