miserable、wretched、unhappy与sorry这些形容词均含“不幸的”之意。

miserable : 指因贫穷、不幸或屈辱等外部因素给人造成精神痛苦、烦恼或肉体折磨，令人同情和可怜。

• We were cold, wet and thoroughly miserable.
  我们又冷又湿，难受极了。
• Don't look so miserable!
  别一副闷闷不乐的样子！
• She knows how to make life miserable for her employees.
  她知道如何整治她的雇员。

wretched : 多指由于疾病、担忧、忧伤等造成的不幸和痛苦，在外表上显得沮丧、可怜、失望，语气比miserable强。

• You look wretched─what's wrong?
  你看起来愁眉苦脸的，怎么啦？
• I felt wretched about the way things had turned out.
  事情落了这么个结局，我感到很难受。

unhappy : 侧重指精神上的不快或失望。

• to be/look/seem/sound unhappy
  感到 / 看来 / 似乎 / 听起来不愉快
• an unhappy childhood
  不快乐的童年
• I didn't realize but he was deeply unhappy at that time.
  我没有察觉到原来他那时非常不开心。

sorry : 常作礼貌用词，表遗憾、婉惜。也指说话人表示同情、悲哀等，感情色彩较强。

• I'm sorry that your husband lost his job.
  你丈夫把工作丢了，我很惋惜。
• We're sorry to hear that your father's in hospital again.
  听说你父亲又住院了，我们心里都不好受。
• No one is sorrier than I am about what happened.
  发生了这样的事，我比谁都难过。