b + scale_fill_brewer(palette = "Set1")也可以使用scale_fill_manual函数自定义颜色 b + scale_fill_manual(values=c(c = "red", d = "blue", e = "green" , p = "orange", r = "yellow"))单一颜色 b+ scale_fill_brewer(palette = "Blues")也可以用scale_fill_grey()函数使用灰度，通过...