考研英语道歉信通常需要包含以下几个部分：
称呼：
根据收信人的身份和关系选择合适的称呼，如“Dear Prof. Patent”或“Dear Susan”等。
道歉内容：
明确表达歉意，说明自己为何道歉，比如未能按时完成任务或未能参加某个活动。
原因说明：
详细阐述导致道歉的具体原因，如突发疾病、时间冲突等。
补偿建议：
如果可能，提出一些补偿措施或解决方案，以显示诚意。
再次道歉：
表达再次道歉的意愿，并希望得到对方的谅解。
结束语：
以礼貌的结束语收尾，如“I sincerely hope we can meet soon”或“Please forgive me for any inconvenience caused”。
```
Dear [收信人姓名],
I am writing this letter to make an apology to you because I failed to [具体事件或任务]。 The reason is that [详细说明原因，如突发疾病、时间冲突等]。 I am sorry that I cannot finish in time, but is there any possibility we can reschedule our meeting？
I understand the importance of [提及事件或任务的重要性]， and I regret causing any inconvenience or frustration by not being able to fulfill my responsibilities. Please accept my sincerest apologies for my mistake.
If there is anything I can do to make up for this, please let me know. I am willing to take any steps necessary to rectify the situation.
once again, I apologize for any inconvenience caused and hope to have the opportunity to make it up to you in the future.
Sincerely,
[你的姓名]
```
请根据实际情况调整信中的内容和语气，以确保道歉信显得真诚且恰当。