By Faiza Elmasry Washington, D.C. 29 March 2007 Watch Healthy Dining report U.S. federal health officials say Americans dine away from home more than ever before. And they say that dining out is a major contributor to the nation's weight problem. To

发表于:2019-01-06 / 阅读(108) / 评论(0) 分类 2007年VOA标准英语(三月)

Once theyve caught the light of a dying star with their state of our telescopes. The detective work can begin. We collect that light and we analyze it in great detail in order to determine whats going on, whats the chemical makeup of the star, whats

发表于:2019-01-22 / 阅读(60) / 评论(0) 分类 自然百科2011年

Under normal circumstances, each of your brain cells allows various substances, such as sodium, calcium and potassium to permeate its outer cell membrane. Once inside the brain cell, these substances help give the cell stimulus it needs to function p

发表于:2019-01-26 / 阅读(56) / 评论(0) 分类 英语听力文摘 English Digest