By Carol Pearson Washington 30 April 2008 Ten years ago, the U.S. Food and Drug Administration approved LASIK, eye surgery with a laser that enables people to see without glasses. But about five percent of LASIK procedures fail, and those patients ca

发表于:2018-12-08 / 阅读(55) / 评论(0) 分类 VOA常速英语2008年(四月)

Converting to Another Religion Debbie: Okay, Im off. Ill be back around eight oclock. Marcelo: Hey, where are you going in such a hurry? Debbie: Im going to my religious education class. Marcelo: Religious education class? Whats that about? Debbie: W

发表于:2018-12-27 / 阅读(59) / 评论(0) 分类 2014年ESL之日常生活

Imagine a world where sunlight can be captured to produce electricity anywhere, on any surface. The makers of thin-film flexible solar cells imagine that world too. But a big problem has been the amount of silicon needed to harvest a little sunshine.

发表于:2019-01-08 / 阅读(65) / 评论(0) 分类 Scientific American(二)月

The nineteenth century held one last great surprise for chemists. It began in 1896 when Henri Becquerel in Paris carelessly left a packet of uranium salts on a wrapped photographic plate in a drawer. When he took theplate out some time later, he was

发表于:2019-01-29 / 阅读(75) / 评论(0) 分类 万物简史

By Paul Sisco Washington 14 November 2007 At the McDonald Observatory in western Texas, a unique space program has been quietly underway for more than 30 years. It is called the Lunar Laser Ranging Program. VOA's Paul Sisco has more. Research scienti

发表于:2019-01-31 / 阅读(73) / 评论(0) 分类 VOA常速英语2007年(十一月)

By Elizabeth Carlassare. Todays topic is what to do if you want to convert to a Roth IRA, but can't. A Roth IRA is a great way to save for retirement if youre eligible to contribute. With a Roth IRA, you contribute after-tax money, but your earnings

发表于:2019-02-05 / 阅读(113) / 评论(0) 分类 货币英语