标签：Cactus 相关文章
Air pollution outside is easy to spot, hanging over the city, or sputtering from a tailpipe. But there's lot of indoor air pollution, too, even if it's not as obvious. It's caused by volatile organic compounds, or VOCs. They can come from building ma
2016年Scientific American(八)月
As humans developed civilizations in Eurasia and Northern Africa, they also domesticated animals for food and labor: horses, cows, goats, pigs, sheep and a few others. But no evidence existed for the deliberate cultivation and breeding of animals in
2016年Scientific American(八)月
By Greg Flakus Cactus, Texas 25 January 2007 On December 12, the United States government carried out the largest nationwide operation against illegal immigrants at their workplaces in U.S. history, arresting 1,300 people at six meat-packing plants
2007年VOA标准英语（一月）
Agriculture Report - Steps Toward Drought-Resistant Crops, 'Designer' Rice This is the VOA Special English Agriculture Report. A discovery in a laboratory could help lead to new generation of drought-resistant crops. Drought conditions cause plants t
2012年VOA慢速英语(一)月
By Greg Flakus Cactus Flat, South Dakota 21 June 2007 During the Cold War, the United States and the Soviet Union targeted each other with thousands of missiles armed with nuclear warheads. Both countries took measures to prevent human or mechanical
2007年VOA标准英语（六月）
By Phuong Tran Katote, Senegal 13 March 2007 In parts of rural Africa, some parents force their daughters to marry as young as eight-years-old. This is so there is no chance the girls can get pregnant before marriage, and ruin the families' honor. O
2007年VOA标准英语（三月）
As Border Crossings Tick Up, Migrants Bring Children, Take More Dangerous Routes AUDIE CORNISH, HOST: The number of immigrants illegally crossing the southern border plummeted when Donald Trump took office, but the number is again on the rise. In res
2018年NPR美国国家公共电台4月