【正确答案】正确答案：Dear Mr. Smith, I am sorry that I shall be unable to attend the English class this morning due to a bad headache. I beg to apply for three days' leave from 20th to 22th. As for the homework I missed, I will do my best to make up and hand them in by e-mail. Yours respectfully, Li Min

【答案解析】解析：1．请假条应简洁明了的说明请假原因、时间。形式和句子长度不要太单调。使用从句比较吸引人。例如：I am sorry that．．． 2．使用词组使句子多样化。例如：make up，hand in 3．使用正式用语更能体现出对老师的尊重。例如：I beg to apply for．．．