单词：magnesia-alumina-silica
硅镁铝合金
单词：magnesia-alumina-silica 相关文章
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,
发表于:2018-12-31 / 阅读(91) / 评论(0)
英语听力文摘 English Digest
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
发表于:2019-01-12 / 阅读(124) / 评论(0)
2015年VOA慢速英语(七)月
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
发表于:2019-01-19 / 阅读(112) / 评论(0)
2018年NPR美国国家公共电台12月
2018年NPR美国国家公共电台12月