单词：4-ethylheptane
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AS IT IS 2014-05-25 Scientists Search for New Ways to Stop Mosquitoes 科学家们寻找新的方法来对付蚊子 The sound of a mosquito can mean trouble in many parts of the world. The bite of a mosquito can be deadly. Today, we will hear about s
2014年VOA慢速英语(五)月
美科学家研发新一代驱蚊剂 In many regions of the world, mosquitoes are a seasonal pest. In other regions, they carry serious diseases like malaria. The World Health Organization estimates that almost 630,000 people died of malaria-related
VOA双语新闻 2014年1月
On its website, a history of the company makes no mention of leador indeed of Thomas Midgleybut simply refers to the original product as containing a certain combination of chemicals. 在它的网站上，公司的历史没有提及铅──也没有提
万物简史
By counting back through these layers and measuring the amount of lead in each, he could work out global lead concentrations at any time for hundreds, or even thousands, of years. The notion became the foundation of ice core studies, on which much mo
万物简史
Lead is a neurotoxin. Get too much of it and you can irreparably damage the brain and central nervous system. Among the many symptoms associated with overexposure are blindness, insomnia, kidney failure, hearing loss, cancer, palsies, and convulsions
万物简史
If you were going to a restaurant and wanted a healthier option, 如果你去饭店，你想吃得健康一点， which would you choose, grilled or fried chicken? 你会选择哪种食品呢，烤鸡还是炸鸡？ Now most people would answer grill
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