old valley filling soil 老谷地堆积土壤
The Valley Heads Moraine prevented old rivers from flowing south, as they had before.
VOA: special.2009.01.05
Yes,you can see horns." These 500 to 1000-year-old cave paintings are young compared to the skeleton of Ardi, an upright hominid more than four million years old discovered in Ethiopia's Great Rift Valley .
VOA: standard.2009.12.14
应用推荐