Does Mr. Lee _____ a big head? [ ]
A. has
B. have
C. is
D. are
答案：B
一共有221袋大米，我一次最多运8袋．至少要运多少次？
冒泡排序在最坏情况下的比较次数是______。
A) n(n+1)/2 B) nlog2n C) n(n-1)/2 D) n/2
