单词：strontium perchlorate
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Soon after taking up his position, Davy began to bang out new elements one after anotherpotassium, sodium,magnesium, calcium, strontium, and aluminum or aluminium, depending on which branch of English you favor. 上任不久，戴维开始宣布发现一
发表于:2019-01-29 / 阅读(47) / 评论(0)
万物简史
万物简史
If we are looking for Martian bugs, we should search for life forms at least as tough and alien as this. Im looking at Mars in a point of view of a microbe. And as a microbe, I really need very, very tiny amount of water. I could probably live my ent
发表于:2019-02-03 / 阅读(35) / 评论(0)
自然百科2012年
自然百科2012年
As July 4th approaches, Americans look to the skies. Throughout the country, fireworks will be launched in celebration of the nation's independence. But what goes up must come down. Reporter Eric Libby looks at the environmental issues surrounding f
发表于:2019-02-04 / 阅读(41) / 评论(0)
VOA标准英语2008年（七月）
VOA标准英语2008年（七月）