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Obama, Romney Differ on Energy Policy President Obama has been a champion of expanding renewable energy sources, such as wind and solar power, which he says hold great promise. Mitt Romney is a proponent of raising production levels of America's own
VOA标准英语2012年(十月)
pH - a measure of how acid or alkali a solution is. As the pH gets lower, the solution is more acid. At a pH of 7 the solution is neither acid nor alkali. pH is the inverse of the logarithm of the con
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This is Scientific American's 60-Second Science. I'm Cynthia Graber. This will just take a minute. Batteries of the future need to deliver more energy, and they need to be smaller. Researchers at MIT think they have developed a technology that can, a
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By Gini Sikes New York 02 February 2006 New York City school children are celebrating Black History Month with an exhibit of portraits of Nelson Mandela at the landmark Rockefeller Center. The show's
2006年VOA标准英语（二月）
By Jessica Berman Washington 01 March 2006 About one-third of U.S. military personnel returning from the war in Iraq use mental health services after their return home, according to a study published
2006年VOA标准英语（三月）
By Patricia Nunan Kathmandu 08 February 2006 Polls have closed in Nepal's controversial municipal elections, which King Gyanendra said would be the first step toward restoring democratic freedoms acro
2006年VOA标准英语（二月）