题干
—I think teenagers should be allowed to make their own decisions when they have problems at school.
—_______. They're not calm enough, after all.
A：I agree
B：I disagree
C：I think so
D：I'm sure
答案(点此获取答案解析）
B
是定义在R上的函数，对任意的实数x，都有
和
的值是（）
