一般来说，认股权证价值的变化幅度（）股价的涨跌幅度。
A.小于
B.等于
C.大于
D.小于或等于
参考答案：C
Yesterday Frank worked deep into the night, this is the second time this week he's stayed up, ____ ? [ ]
A. didn't he
B. isn't it
C. isn't this
D. hasn't he
【问题2】 什么是DoS攻击
