题干
– The drunk driver wishes he _________ so many injuries in the accident.
– But he _________.
– But he _________.
A：hadn’t caused; had
B：didn’t cause; did
C：hadn’t caused; did
D：hasn’t caused; ha
答案(点此获取答案解析）
C
关于运算
满足：（1）对任意
、
，都有
；（2）存在
，使得对一切
，都有
，则称
{非负整数}，