精选优质文档-倾情为你奉上The United StatesI. Choose the correct answer.1. In area, the United States is the largest country in the world.a. 2ndb. 3rdc. 4thd. 5th 2. The Midwest in the US refers to the region .a. west of the Mississippi Valleyb. west of the Appalachian Mountainsc. east of the Rocky Mountainsd. around the Great Lakes and the upper Mississippi Valley.3. The Backbone of North America refers to the .a. Appalachian Mountainsb. R
