——Why are the housing prices in big cities going up all the time? —————One reason is that

问题补充：

——Why are the housing prices in big cities going up all the time? —————One reason is that people are into overcrowded cities in great numbers.

A. breaking

B. filling

C. pouring

D. hurrying

答案：

A. breaking

B. filling

(答案→)C. pouring

D. hurrying

解析：pouring表示人流涌进。