U 良心 person's awareness of right and wrong with regard to his own thoughts and actions

　appeal to sb's ～　呼吁某人的良知
　arouse〔rouse〕 sb's ～　唤起某人的良知
　consult one's ～　扪心自问
　follow one's own ～　凭良心办事
　satisfy one's ～　使自己心安理得
　social ～　社会良知
　uneasy ～　不安的良心
　against ～　违背良心
　with a good ～　问心无愧
　with a safe ～　心安理得

　I had a guilty conscience about not telling her the truth.　我因为没有告诉她事实真相而感到内疚。
　After he had committed the crime, his conscience was troubled.　他犯罪后，良心上感到很不安。