在写英语请假邮件时，留学期间通常需要遵循以下结构和表达方式：
称呼
使用适当的尊称，如 "Dear Mr./Ms. [姓氏]" 或 "Dear [老师的名字]"。
自我介绍
简要介绍自己，包括姓名和学校。
请假原因
清楚、简洁地说明请假的原因。
请假时间
明确请假的开始和结束日期。
承诺补回时间
如果可能，说明会补上错过的课程或工作。
结束语
表达感谢和期待回复。
```
Dear [老师的名字],
I hope this email finds you well. My name is [你的名字], and I am a student in the [课程名称] class at [学校名称]. I am writing to request a leave for [请假开始日期] to [请假结束日期].
The reason for my leave is [请假原因，例如：I have been invited to a family wedding in my hometown, and it is a significant event for my family that I cannot miss.]
I understand the importance of attending all classes and maintaining a good academic record. Therefore, I have arranged with a fellow classmate to take notes on my behalf and will ensure to catch up on all the missed coursework upon my return.
If there are any assignments or exams during my absence, I will make sure to submit them as soon as possible after returning.
Thank you for your understanding and support. I look forward to your reply.
Sincerely,
[你的名字]
```
请根据实际情况调整邮件内容，确保所有信息都是准确和恰当的。