题目

—Look! What a nice garden! —Yes. It ______ every day. A. is cleaned                                      B. has been cleaned      C. is being cleaned                              D. was cleaned 答案：A若，，定义： ，例如：=(-5)(-4)(-3)(-2)(-1) =-120,则函数的奇偶性为（    ） A．是偶函数而不是奇函数          B．是奇函数而不是偶函数 C．既是奇函数又是偶函数         D．既不是奇函数又不是偶函数