物理安全是指对信息系统所涉及到的()、()和办公环境等进行物理安全保护。
参考答案:主机房;辅助机房
—Did you see Tom at the party ?
—No, he _____ by the time I got there . [ ]
A. left
B. was leaving
C. had left
D. has left
某生在整理归纳中国近现代外交关系史时,粗略地绘制了一个两国关系发展趋势图,该生试图揭示的是
A.中德关系趋势
B.中美关系趋势
C.中苏关系趋势
D.中日关系趋势