a part - of 的a可以去掉嗎

a可以去掉，例如：

1、Part of the path had been washed away by the sea.部分小路已被海浪衝壞。

2、I'm putting by part of my wages every week to buy a bike.我每個星期把一部分工資存起來準備買輛自行車。

3、This unit is now an established part of the course.這個單元現在為本課程既定的一部分。