电子商务框架有两个支柱，即社会人文性的______和自然科技性的技术标准。
A．安全标准 B．政策法规C．道德规范 D．经济基础
参考答案：B
．---The movie 2012 will be on at 8 pm．What about picking you up at 7?
---All right．I will have come back from work by their, and I_________you at home．
A．will be waiting for
B．will wait for
C．have been waiting for
D．am waiting for
—Tim ____ the science test last weekend. What about you, Peter?
—I ____ English. [ ]
A. studied; studied
B. studied for; studied
C. studied for; studied for
D. studied; studied for
