Dear Prof. Richard, 　　I am a postgraduate student of the English Department of our university. I am writing this letter to ask whether you can help me with my master thesis. 　　I am preparing for a master thesis on American culture, but it is difficult for me to find enough reference materials. As we all know, you are a distinguished authority in this field and have published quite a few wonderful books related to my thesis, so I hope you can offer me some useful suggestions or materials. I firmly believe your help will enrich my knowledge and broaden my horizon. 　　Thank you for your consideration, and I am looking forward to your favorable reply at your earliest convenience.