单词：silica mineral
单词：silica mineral 相关文章
By David Lewis A natural resources watchdog group issued a report Tuesday warning that smuggling and corruption are costing the Democratic Republic of Congo millions of dollars a month in lost revenue
VOA2004（下）--世界经济
Plant Self-defense Plants may appear to be helpless in the face of hungry,toothy animals but many plants have evolved interesting systems of self-defense. Coarse meadow grasses are a good example. If you run your finger along a blade of coarse grass,
英语听力文摘 English Digest
AS IT IS 2015-07-14 Silica Sand Mining Worries Communities 美国硅砂矿引发社区担忧 The United States is increasing production of oil and natural gas through a process known as fracking. This process is sometimes called hydraulic fracking be
2015年VOA慢速英语(七)月
Harnessing the Mineral Wealth of Poor Countries 新方针指导贫穷国家正确利用其丰富矿藏 Developing countries with potential mineral riches have often fallen prey to corruption and mismanagement. As a result, theyve failed to benefit fr
VOA标准英语2012年(二月)
Cameroon's new mineral research center will begin operations this year. South Korean mining researchers are making trips to Cameroon to determine the overall cost of the facility, to be located in the capital, Yaounde. They say the center will cost s
VOA标准英语2011年(二月)
AILSA CHANG, HOST: Despite mounting evidence and a stream of dire warnings, federal regulators and mining companies failed to protect coal miners from toxic dust. MARY LOUISE KELLY, HOST: NPR and the PBS series Frontline spent more than a year lookin
2018年NPR美国国家公共电台12月