在最坏情况下，冒泡排序所需要的比较次数为 【1】 。
参考答案：n(n-1)/2
解析： 在最坏情况下，冒泡排序所需要的比较次数为n(n-1)/2。
Saddam and his followers ______ from Baghdad before the air raids took place. [ ]
A. had escaped
B. has escaped
C. was escaping
D. escape
置换固溶体和间隙固溶体都有可能形成无限固溶体。（）
