单词：duration of filtration cycle
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Beijing will launch a pilot program to equip schools and kindergartens with air filtration devices. Smog has been a significant issue in the Chinese capital this winter. I was coughing just now, I always wear mask, from school to home. The air is cho
2017CRI中国国际广播电台
Water Cycle 水循环 All the oceans on earth are salty, while inland water is typically fresh. How does water become salty? We'll answer a listener's question -- today on Earth and Sky. DB: This is Earth and Sky. We recently visited the Austin Childr
(科普英语)Earth and Sky
DIDA: Taki Sun, 28 Nov 93 Duration: 36 mins Sue Lawley's castaway is the journalist Taki.
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Fire Cycle 火灾规律 The El Nino phenomenon of 1997-98 unleashed torrential rain in some parts of the world, while creating abnormally dry conditions in others. And it sparked record numbers of wildfires. Learn more about climate and wildfire -- toda
(科普英语)Earth and Sky
By Tabinda Naeem Washington, D.C. 21 May 2007 Two years ago, the National Academy of Engineering established the Grainger Challenge Prize for Sustainability. This $1 million award was designed to challenge the world's scientists to develop a practica
2007年VOA标准英语（五月）
Classical music fans in Beijing are now embracing a massive work-the complete cycle of Beethoven's 9 symphonies with The Deutsche Kammerphilharmonie Bremen. Paavo Jarvi, an internationally famous Estonian conductor, is the artistic director of the or
2017CRI中国国际广播电台