用英文寫一張因頭痛而不能去上課的請假條

題目：

用英文寫一張因頭痛而不能去上課的請假條

解答：

To whom this may concern:
Dear Sir or Madam,
I'm afraid that I may not be able to attend the class today for I'm suffering from a bad headache.
I would be very grateful if you could kindly excuse my absence.