单词：sym-dichloroacetone
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Air pollution outside is easy to spot, hanging over the city, or sputtering from a tailpipe. But there's lot of indoor air pollution, too, even if it's not as obvious. It's caused by volatile organic compounds, or VOCs. They can come from building ma
2016年Scientific American(八)月
If you are like many language students, you might have a problem with procrastination. Perhaps you are slow to do homework or study for a test. Maybe you do not like to study or you become distracted while studying. Whatever the case may be, learning
2017年VOA慢速英语(六)月
By Al Pessin Pentagon 24 March 2008 When a roadside bomb killed four American soldiers in Baghdad Sunday night it brought the U.S. military death toll in Iraq to 4,000. It was a symbolic moment, particularly coming during a period of reduced violence
VOA标准英语2008年（三月）
Some Zimbabwe government supporters say President Robert Mugabe should form a government without the opposition, following an opposition boycott of talks Monday in Swaziland. Tendai Maphosa asked ordinary Zimbabweans in Harare what they think about
VOA标准英语2008年（十月）
BEIJING, Aug. 8 (Xinhua) -- China on Wednesday started to review anti-dumping measures it imposed on chloroprene rubber imported from a Japanese company, the Ministry of Commerce said. The move came after the ministry received complaints that Japan E
英语新闻
Cement is a major component of concrete, the world's most widely used man-made material, an integral part of roads, bridges and buildings. But making cement requires heating limestone and other materials to very high temperatures, a process that rele
VOA标准英语2010年(一月)