信息系统安全层次模型中实体安全不包括（）
A.场地环境安全
B.硬件安全
C.网络安全
D.介质安全
参考答案：C
古代雅典城邦平民能在反对贵族的斗争中取得胜利，最重要的社会因素是[ ]
A、平民开展暴力斗争
B、代表平民利益的领袖不断改革
C、平民中不再有债奴
D、平民中新兴工商业者力量壮大
The shop _____ for two weeks, but I _____ there so far.[ ]
A. has opened; haven't gone
B. has been open; haven't been
C. has been open; haven't gone
D. has opened; haven't been
