题目

Tony feels more (energy)after a short time of rest. 答案：【1】energetic若f(x)对任意实数x恒有2f(x)－f(－x)＝3x＋1，则f(x)＝(　　) A．x－1                            B．x＋1 C．2x＋1                           D．3x＋3