forgetful: implies a heedless or negligent habit of or propensity for failing to remember: ~ of my duties as a host.


oblivious: suggests a failure to notice or remember as a result of external causes or conditions  OR of a determination to ignore: lost in thought, ~ to the rushing crowd around her.


unmindful: may suggest inattention and heedlessness OR a deliberate disregard: a crusading reformer who was ~ of his family's needs.


forgetful健忘: 表示经常容易忘事(habit习惯暗指经常，propensity倾向暗指容易)，比如由于粗心或年龄，oblivious没注意或忘记: 表示没有注意或没有记住，可指无意或有意（原文比较长“由于外部因素或自身故意忽视而没有注意到或忘记"意思是"既可指无意也可指有意"，forgetful指无意即不是故意的），unmindful忘记或不顾: 同样可表示没注意到或不顾（disregard语气比ignore委婉，因此例句选此词）


记忆方法: 1）首字母FOU想成飞碟<==看到后忘记


              2）忘记的意思是失去对某事的记忆mean losing from one's mind something once known or learned.