【判断题】By the mid-19th century, the territory of the United States had reached over 10 million square kilometers, about 9 times the size of the total area of the original thirteen states.
【多选题】第三章7.各地要根据实际需要,在()等建设旅游咨询中心。
【简答题】Sandstorms( 沙尘暴 )happen suddenly and have effects on large areas. One example was a sandstorm on the Western Route. It moved quickly southward( 向南 )from May 4th to 6th, 1993, having effects on a total...