Computers will flourish because they enable us to accomplish tasks that A．could never before have been undertaken B．would never before have undertaken C．couldn't be undertaken D．mustn't have been undertaken
A.could B.would C.couldn't D.mustn't
【参考答案】
A 此题只要正确理解了句子的意思，做出正确选择并不难。句意为：'计算机使人们得以干以前干不了的事，因此它将兴旺发......