(Ⅰ)求函数f (x)的最小正周期;
(Ⅱ)求函数f (x)的单调减区间.
在对吸烟与患肺病这两个分类变量的计算中,下列说法正确的是( )
-- Don't touch the papers.
-- ____ (certain), I'll not let the papers be touched.