A. George Washington, the 1st American president B. Christopher Columbia, the discoverer of the American continent C. Both George Washington and Christopher Columbia D. Neither of them
单项选择题Grand Canyon, one of the great natural wonders of the world, is located in ().
A. Wisconsin B. Tennessee C. Arizona D. Colorado
单项选择题() is reputed as the automobile capital of the world.
A. Chicago B. Detroit C. New York D. Washington D. C.
