3、Justice is part of the complex machinery of the law.

part of ：部分, 前面没有冠词

--Only part of his story is true. 他的话有一部分是真实的

parts of : 几部分，若干部分

--Parts of the log book were recognized. 航海日志的若干部分还是能被辨认出来的.

--Large parts of the house were destroyed in the fire.房屋的大部分在火灾中烧毁了。

无论是 part of 还是 parts of 后面都要带单数名词

4、Those who seek it, undertake an arduous journey and can never be sure that they will find it.

那些追寻正义的人，可以说是踏上了一条漫长崎岖而且艰难的道路。

Judges, however wise or eminent, are human and can make mistakes.

法官无论如何聪明与有名，毕竟也是人，也会出差错的。

however=no matter how

5、There are rare instances when justice almost ceases to be an abstract concept.

在个别情况下，正义不再是一种抽象概念。

There are rare instances when ：在极个别的情况下。

--There are rare instances when women are not equal to men.

在极个别的情况下，女士和男士是不平等的。

cease: (正式)彻底的停止，暗指动作的突然性

--His heart suddenly ceased to beat. 他的心脏突然停止了跳动。