for conscience' sake

1. 为了良心上过得去
   She returned the money to him for conscience' sake.

   为了良心上过得去，她把钱还给了他。

have no conscience

1. 没有良心；不辨是非
   How could he have done such harm to her! He's got no conscience at all.

   他怎么能这样伤害她！真是一点良心也没有。

have the conscience to do sth.

1. 厚着脸皮做某事
   He had the conscience to do such a thing.

   他竟有脸做这种事！

in all conscience

1. 凭良心
   He couldn't do such a thing in all conscience.

   从良心上来讲，他不能做这种事。

on one's conscience

1. 问心有愧
   How could he live peacefully with such a wicked crime on his conscience?

   他做了这样伤天害理的事怎么能过太平的日子呢？

• in (all) conscience
  in fairness.
• on one's conscience
  causing feelings of guilt.