Not until all the fish died in the river ________ how serious the pollution was.

A．did the villagers realize

B．the villagers realized

C．the villagers did realize

D．didn’t the villagers realize

“市场总是在扩大，需求总是在增加。工场手工业也不能满足这种需求了。于是蒸汽和机器就引起了工业中的革命。”由此看出直接引发工业革命的因素是 

A．殖民扩张和掠夺的需要

B．蒸汽与机器的结合

C．不断扩大的市场的需求

D．资本主义制度确立