A:took part in; joined
B:took part in ; joined i
C:joined in; took part i
D:joined; took part
世界上信徒最多和流传最广的宗教是
改革开放以来,我国乡村人口疏化现象日趋严重,读下表,回答问题。
(Ⅰ)求函数f (x)的最小正周期;
(Ⅱ)求函数f (x)的单调减区间.