英文回答：
Dear Professor,。
I am writing to you today to inform you that I have decided to withdraw from your course. I have enjoyed your class very much, but I have recently found myself
struggling to keep up with the workload. I am a full-time student and also work part-time, and I have found it difficult to balance my time between school and work. I am concerned that if I continue to take your course, I will not be able to do my best work.
I apologize for any inconvenience this may cause. I hope to be able to take your course again in the future when I have more time to devote to it.
Thank you for your understanding.
Sincerely,。
[Your name]
中文回答：
尊敬的教授，。
我写信给您是为了通知您，我已决定退出您的课程。我很享受您的课堂，但我最近发现自己难以跟上课程进度。我是个全日制学生，还有份兼职工作，我发现很难平衡学校和工作上的时间。我担心如果我继续选修您的课程，我将无法尽我所能做好。
对于由此造成的不便，我深表歉意。我希望将来我有更多时间投入时，可以再次选修您的课程。
感谢您的理解。
此致，。
[您的姓名]
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