[单项选择]Without transportation, there could be no trade. Without trade, there could be no towns and cities. Towns and cities are traditionally the 16 of civilization. Therefore, transportation helps make civilization 17 . Throughout most of the prehistoric period, people lived by hunting, fishing, and 18 wild plants. They had no beasts of burden, wheeled vehicles, or roads. People traveled 19 and carried their infants and belongings strapped to their backs or heads. Loads too heavy for one person to carry were strapped to a pole and carried by two people. 20 , people learned that they could drag loads along the ground on sledges. During late prehistoric times, people began to build sledges with runners. When people developed agriculture and began to establish 21 settlements, trade between settlements started to develop, which created a need for better 22 of transportation. The donkey and the ox, which had been tamed for food products and farm work, helped 23 this need. The
A. powered
B. controlled
C. oriented
D. related

[单项选择]Without transportation, there could be no trade. Without trade, there could be no towns and cities. Towns and cities are traditionally the 16 of civilization. Therefore, transportation helps make civilization 17 . Throughout most of the prehistoric period, people lived by hunting, fishing, and 18 wild plants. They had no beasts of burden, wheeled vehicles, or roads. People traveled 19 and carried their infants and belongings strapped to their backs or heads. Loads too heavy for one person to carry were strapped to a pole and carried by two people. 20 , people learned that they could drag loads along the ground on sledges. During late prehistoric times, people began to build sledges with runners. When people developed agriculture and began to establish 21 settlements, trade between settlements started to develop, which created a need for better 22 of transportation. The donkey and the ox, which had been tamed for food products and farm work, helped 23 this need. The
A. highlights
B. pinpoints
C. headquarters
D. centers

[单项选择]

Transportation Decision Transportation decision consists of the following parts: 1.Selection of the mode is determined by the consideration of distance,cargo weights,linkage,timing and other requirements.Generally speaking,rail has high fixed cost and the relatively low variable cost.It can move heavy,large quantity of cargo in the long distance.But,rail is disadvantaged because of the longer transit time and less frequent service than motor. Motor carriers such as truck companies offer door-to-door service,that is,the cargo can be shipped from the shipper＇swarehouse to the consignee＇s.Trucking fixed cost is the lowest of any carrier,because the equipment is fairly cheap and the motor carriers do not have to invest in the roads on which they run their operations.However,their variable costs are very high.Its expenses include two major components:firstly,the pick-up and delivery costs;secondly,there are gas or fuel costs,labor expenses and toll roads fees to be paid to highway and
A. By railway.
B. By water.
C. By air.
D. By trucks.