Well, that's limelight. What exactly was it? Well it was the burning of calcium oxide in a very intense flame. And when did the job of a limelighter begin? Oh, famously, the first recorded instance in

发表于:2018-12-07 / 阅读(31) / 评论(0) 分类 圣诞特辑

Broadcast: February 14, 2003 By George Grow This is the VOA Special English Environment Report. President Bush has offered a plan to speed development of technology that uses hydrogen as fuel. His goa

发表于:2018-12-07 / 阅读(74) / 评论(0) 分类 VOA2003(上)-科技导航

I am speaking not as a Briton, not as a European, not as a member of a western democracy, but as a human being, a member of the species Man, whose continued existence is in doubt. The world is full of conflicts: Jews and Arabs; Indians and Pakistanis

发表于:2018-12-12 / 阅读(56) / 评论(0) 分类 英语演讲

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

发表于:2019-01-03 / 阅读(59) / 评论(0) 分类 医务英语

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

发表于:2019-01-08 / 阅读(78) / 评论(0) 分类 Scientific American(四)月

December 30, 1954 I am speaking not as a Briton, not as a European, not as a member of a western democracy, but as a human being, a member of the species Man, whose continued existence is in doubt. The world is full of conflicts: Jews and Arabs; Indi

发表于:2019-02-09 / 阅读(45) / 评论(0) 分类 英语美文