题干
You can’t camp you like these days. Many natural areas are now under protection.
A：what
B：whe
C：wherever
D：which
答案(点此获取答案解析）
C
,定义函数
,若
两两不相等，且
为不小于6的偶数，则满足上述条件的不同的函数
有（ ）个