题干
____________ English well, one must have a lot of practice.
A：Speaks
B：To speak
C：Spoken
D：Speak
答案(点此获取答案解析）
B
____________ English well, one must have a lot of practice.
A：Speaks
B：To speak
C：Spoken
D：Speak
在定义域（-1,1）上是减函数，且
，则
的