分担向信息市场提供信息产品职能的是( )
A．开发产业
B．知识产业
C．传播产业
D．信息流动产业
E．经营产业
参考答案：A,B,C,D
I made a call to my parents yesterday. To my disappointment, ______ of them answered it. [ ]
A. either
B. none
C. neither
D. nobody
已知x为实数，化简︳x-3︳+︳x+3︳的结果．
