Lucy: Hi, Mike.____?

Mike: No, it's Friday.

Lucy: ____?

Mike: We have English, social studies, art and PE.

Lucy: Tomorrow is Saturday. We don't go to school.____?

Mike; I often read books on Saturdays.____?

Lucy: I often play basketball with my father.

Mike: So great!____?

Lucy: He's tall and strong.

函数$f\left(x\right)$的定义域为D，若对于任意$x_1,x_2\in D$，当$x_1<x_2$时都有$f\left(x_1\right)\le f\left(x_2\right)$，则称函数$f\left(x\right)$在D上为非减函数，设函数$f\left(x\right)$在0，1上为非减函数，且满足以下三个条件：①$f\left(0\right)=0$；②$f\left(\frac{x}{3}\right)=\frac{1}{2}f\left(x\right)$；③$f\left(1-x\right)=1-f\left(x\right)$，则$f\left(\frac{1}{3}\right)+f\left(\frac{1}{8}\right)$等于（   ）