单词：silica minerals
单词：silica minerals 相关文章
Rare Minerals May Be in North Korea 稀有矿物质可能在朝鲜发现 Hello and welcome back. Im Jim Tedder in Washington. Today we are going to talk about something that is worth a lot of money, and it is buried in the ground. Were not exactly go
2014年VOA慢速英语(二)月
Bipartisan legislation on so called conflict minerals was recently introduced in the US House of Representatives. The bill is designed to create transparency and allow consumers to make informed choices when they purchase electronic devices like cel
VOA标准英语2009年(十一月)
第一句： We have been importing and exporting all kinds of metals and minerals for thirty years. 我们经营各种金属和矿石的进出口业务已经有30年了。 A: We have been importing and exporting all kinds of metals and minerals for
天天商务口语
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
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