填空题large cities

单项选择题A．The new technology used to build roads.B．The ability to transport goods over land.C．The trade in grain and cotton.D．The linking of smaller local roads into one long road.

单项选择题A．Poor visibility.B．Slippery conditions caused by the rain.C．Both A andB.D．The narrow national highway.

单项选择题A．The advantages of an economy based on farming.B．Reasons farmers continued using river transportation.C．The role of cotton in the United States economy.D．Improved methods of transporting farm crops.

单项选择题A．Get the results of the survey back.B．Draw the results of the survey.C．Make some conclusions.D．Collect more information