对n个记录的文件进行快速排序，平均执行时间为
A．O(log2n)
B．O(n)
C．O(olog2n)
D．O(n2)
参考答案：C
. After he graduated from college, he _______ his father’s business.
A．took over
B．took up
C．took in
D．took on
按照业务方式，可将快件分为保价快件、保险快件和普通快件三类。
