单项选择题
A．Dark blue brings tragedy. B．Dark blue means tradition. C．Dark blue represents night. D．Dark blue indicates quietness.
A．poor quality rails and unreliable stopping systems B．lack of financial support for development C．limited railroad lines D．lack of a transcontinental railroad
A．brought about a rapid growth of industry and farming in the west B．attracted many visitors to the construction sites C．attracted laborers from Europe D．encouraged people to travel ail over the country