This maths problem is a bit difficult fot me to work out.

问题描述:

This maths problem is a bit difficult fot me to work out.
为什么bit difficult前面要加a?

a bit 是固定短语,跟a little 一样.a little 和little 的区别知道吧?就是类似的.
如果不要a ,只要bit的话,就是否定的意思,几乎没有.a bit 就是有一点