Bacteria are extremely small living things. While we measure our own sizes in inches or centimeters, bacterial size is measured in microns. One micron is a thousandth of a millimeter: a pinhead is about a millimeter across. Rod-shaped bacteria are u

发表于:2018-11-28 / 阅读(424) / 评论(0) 分类 新概念优美背诵短文50篇

Bacteria are extremely small living things. While we measure our own sizes in inches or centimeters, bacterial size is measured in microns. One micron is a thousandth of a millimeter: a pinhead is abo

发表于:2018-12-01 / 阅读(141) / 评论(0) 分类 新东方背诵文选

By Ruth Reader Washington, DC 13 February 2008 There is growing concern around the world over illnesses caused by new antibiotic-resistant bacteria, or so-called superbugs, and the decreasing effectiveness of antibiotics to treat infections. Earlier

发表于:2019-01-07 / 阅读(67) / 评论(0) 分类 VOA常速英语2008年(二月)

Experts: Let Produce Dry Out to Avoid Bacteria American researchers say farmers should wait one day after a rain storm or watering their fields to harvest fresh fruits and vegetables. They say gathering the crops at least 24 hours after rainfall incr

发表于:2019-01-12 / 阅读(112) / 评论(0) 分类 2015年VOA慢速英语(七)月

After Independence, South Sudan Faces Serious Challenges Ahead As the euphoria from a hard-won independence subsides, South Sudan now must turn to face enormous development challenges. Meanwhile, the threat of a return to war and outstanding politica

发表于:2019-01-13 / 阅读(22) / 评论(0) 分类 VOA标准英语2011年(十二月)

In Colorado, Solar Industry Faces Challenges Colorado's San Luis Valley, an alpine desert, is rapidly becoming a leading producer of solar energy in the United States. The sun shines more than 340 days a year in the San Luis Valley. So the solar indu

发表于:2019-02-07 / 阅读(46) / 评论(0) 分类 VOA标准英语2011年(十二月)