已知函数。
（Ⅰ）求f（x）的定义域与最小正周期；
（Ⅱ）讨论f（x）在区间上的单调性。
参考答案：
—I was asked to attend the meeting before eight.
—Oh, you________. I'm sorry for not telling you that we have changed the plan.
A．must
B．can't
C．may
D．needn't
There isn't tea now. Would you like juice? [ ]
A. any; some
B. some; any
C. any; any
D. some; some
。
上的单调性。
。上的单调性。