a bit ,a bit of ,a few ,a few of有什么区别

问题描述:

a bit ,a bit of ,a few ,a few of有什么区别
什么时候有of?

a bit +adj 表示“一点儿”,其后不可直接加名词;a bit of +n 表示“有一些”,a bit of =a little .
a few和a few of都表示“几个,一些”,不同的是a few students=几个学生,a few是量词;a few of students学生中的几个,a few是代词.