LOS ANGELES, June 21 (Xinhua) -- North Dakota Governor Kelly Armstrong declared a statewide disaster on Saturday after three people were killed in a violent tornado that tore through the Upper Midwest ...

龙卷风。图片由 Justin1569 提供，位于英语维基百科，CC BY-SA 3.0 http://creativecommons.org/licenses/by-sa/3.0/，来自 Wikimedia Commons。 几个 ...