a bit ,a bit of ,a little,a little of,a few of ,a few,这几个哪个是正确的？它们后面各接什么词？

a bit 后面通常跟形容词 一点儿 a bit warm 有点儿热
a bit of 后面跟名词 a bit of luck 一点儿运气
a little 后面跟不可数名词，一些 a little water
a few 后面跟可数名词的复数形式 一些 a few apples

全部正确的啊。。
就看在具体的环境怎么用了。。。