penitence: implies sad and humble realization of and regret for one's misdeeds: willing to forgive when faced with the outward signs of ~. (很容易错写成’pentinence’，联想penny发音: 因为1分钱忏悔)

repentance: adds the implication of an awareness of one's shortcoming and a resolve to change: a complete change of character accompanied his ~.

contrition: stresses the sorrowful regret that accompanies true penitence: the beatings were usually followed by tearful ~.

compunction: implies a painful sting of conscience for past or especially for contemplated wrongdoing: have no ~ about taking back what is mine.

remorse: suggest prolonged and insistent self-reproach and mental anguish for past wrongs especially for those whose consequences can not be remedied: swindlers are not usually plagued by feelings of ~.

penitence: 表示感到悲哀惭愧和后悔错误行径，repentance: 进一步意识到缺点并决心改正，contrition: 强调忏悔时的悲哀(sorrow)，compunction: 因为错误行径(常故意contemplate沉思)而刺痛良心， remorse: 因为造成无法挽回的伤害，而长时间的自责和精神痛苦(anguish精神极度痛苦)。

记忆方法: 1) 首字母联想，PRC RC: 日本应该对新旧中国忏悔。
  

                                     PRC: People’s Republic ofChina中华人民共和国

                                     RC: Republic of China中华民国

              2) 忏悔的意思是: 为错误或恶行(sin)后悔，mean regret forsin or wrongdoing.