I would appreciate your approval to attend our class. Here are the details.
I would like to inquire about the products listed on your website.
We wish to remind you that the deadline is approaching.
I am writing this letter to request the cancellation of the room booked by Mr. Liu yesterday.
I am writing this letter to complain in the strongest terms about the terrible service I have received from your company.
We are writing you with reference to your interest in the event mentioned previously.
With reference to
With reference to your letter of last week, we think it necessary to continue our cooperation.
Thank you for writing to us about your experience in our shop last week.