防攻击指标:在工信部备案的2级以上系统和省级电信公司自有DNS遭受攻击导致业务基本不可用的安全事件≤()次/年。
A.1
B.3
C.5
D.6
参考答案:C
非洲经济落后的原因[ ]
A.自然环境恶劣
B.政府不重视
C.长期殖民统治
D.人们思想意识落后
But for the help of my English teacher, I the first prize in the English Writing Competition.[ ]
A. would not win
B. would not have won
C. would win
D. would have won