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27. Scientific Theories In science, a theory is a reasonable explanation of observed events that are related. A theory often involves an imaginary model that helps scientists picture the way an observed event could be produced. A good example of thi
新概念优美背诵短文50篇
When they hear the name Ben Franklin, many folks think of the Declaration of Independence, the Continental Congress and things like that. Not as many people remember that Franklin was an inventor . . . and a good one, too! He also did some pioneering
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The most powerful atom smasher ever built could make some bizarre discoveries, such as new forces of nature or even extra dimensions of space, after it's switched on in August. The Large Hadron Collider, or LHC, basically consists of a ring of super
国家地理2008年
This is AP News Minute. Republican Senator Cindy Hyde-Smith won Mississippi Senate election run-off. She defeated Democrat Mike Espy and becomes the first women elected to Congress from Mississippi. The Chinese scientist who claimed to have help make
美联社新闻一分钟2018(十一)月
A World Health Organization panel of medical ethicists has ruled it is ethical to offer unproven drugs or vaccines to people infected or at risk of infection in West Africa's deadly Ebola outbreak. Meanwhile, one of three Chinese medical teams sent t
2014CRI中国国际广播电台
One of the world's foremost analysts of North Korea's ballistic missile programs says reports of missile engine testing at a newly revealed facility appear credible. North Korea is apparently able to test its missiles under more realistic conditions
VOA双语新闻 2008年9月
When I was six years old, my first grade teacher had this brilliant idea. She wanted us to experience receiving gifts but also learning the virtue of complimenting each other. And she said, Why don't we just stand here and compliment each other? If y
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