单词：convex head piston
单词：convex head piston 相关文章
In Australia, its not just livestock hit hard by draught, but the next generation of farmers. At 24, Robert Watt, a farmer from Alectown, a region of Australia, has had seven seasons on the farm, but not one year of profit. He says the draught, plus
自然百科2016年
In Australia, its not just livestock hit hard by draught, but the next generation of farmers. At 24, Robert Watt, a farmer from Alectown, a region of Australia, has had seven seasons on the farm, but not one year of profit. He says the draught, plus
国家地理2008年
ECONOMICS REPORT - Economic News in 2005 By Mario Ritter Broadcast: Friday, December 30, 2005 I'm Steve Ember with the VOA Special English Economic Report. Today, we look back on some top stories of t
健康与经济
By Peter Heinlein Addis Ababa 15 May 2008 Growing enough food to alleviate shortages in African countries is not easy, but an agro-ecologist in Ethiopia thinks he has the answer: bio-farming. The technique uses animal waste products to produce energy
VOA标准英语2008年（五月）
Researchers get same yields with fewer fertilizers, pesticides Steve Baragona | Washington, DC 18 May 2010 Fossil energy use was compared among different crop rotation systems in a field experiment conducted between 2003 and 2008 in Boone Co., Iowa R
VOA标准英语2010年(五)月
In Afghanistan, the vast majority of the population relies on agriculture for its livelihood. Three decades of war have not changed the central importance of farming in this country, only its difficulty. Afghanistan's U.S.-educated Minister of Agricu
VOA标准英语2011年(一月)