题目

The dictionary is exactly expensive than that one. A . five times as B . five times more C . five times D . as five times 答案：B已知定义在R上的函数f（x）是奇函数且满足f（-x）=f（x），f（-2）=-3，数列{an}满足a1=-1，且=2×+1，（其中Sn为{an}的前n项和）．则f（a5）+f（a6）=（ ）A．-3B．-2C．3D．2