题干
— Were there any cows?
— ________.
A：Yes, there were
B：No, there aren't
C：Yes, there are
D：No, there were
答案(点此获取答案解析）
A
— Were there any cows?
— ________.
A：Yes, there were
B：No, there aren't
C：Yes, there are
D：No, there were
上的偶函数
，对于任意的
都满足：
，当
时
，则（ ）