以下哪一个不属于网络文化建设的正确行为（）
A.发展网络新技术
B.整治低俗信息
C.限制社交网站
D.保护网上个人信息
参考答案：C
The goal of a “competition” may simply be ______ fun and enjoy the excitement of trying something new. [ ]
A. to have
B. having
C. having had
D. have
调车作业的单一指挥是怎样规定的？
