相对而言，属于不可燃的物质是：（）
A、木材
B、二甲苯
C、四氯化碳
D、丙酮
参考答案：C
用所给的物主代词填空。
My your his her
1. -Is this your toy car?
-Yes, it's _________ toy car.
2. -Is that her radio?
-No, it's not _________ radio. It's _________.
3. -This is _________ book, I think.
-No, it’s not my book.
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)
