(20 1 1? Read the graphic materials about Beijing-Shanghai high-speed railway and answer this question. Materials Beijing-Shanghai high-speed railway is the longest railway in the world.

(1) As can be seen from the map, the Beijing-Shanghai high-speed railway starts from Beijing in the north and reaches Shanghai in the south, passing through the North China Plain and the middle and lower reaches of the Yangtze River, connecting the Bohai Rim region and the Yangtze River Delta region.

(2) China's basic national conditions are a large population with little land resources. Therefore, in order to save land resources in the eastern region, beijing-shanghai railway has given priority to the construction of "replacing roads with bridges".

(3) Qinling Mountain and Huaihe River are important geographical boundaries in eastern China, and there are significant differences in natural environment, geographical landscape and residents' production and living habits between the north and the south. The natural geographical significance includes the place where the China 1 month 0℃ isotherm passes, and the place where the 800 mm annual isohyet in China passes. The significance of human geography includes the boundary between south and north of China, and the boundary between dry land and paddy field in China.

So the answer is: (1) North China; Middle and lower reaches of the Yangtze River; Yangtze river delta; (2)B； (3) 1 0℃ isotherm; The dividing line between the south and the north.