填空题

34, Block A, 15th Floor
Blake Avenue
Singapore 18
15th February, 2008
The Editor
Readers Write
The New Echo
Alexandra Road
Singapore 3
Dear Sir,
I must write through your column to thank the gentleman who very kindly helped me and my family a few nights ago. It was raining heavily at the time and my car had broken down along a lonely stretch outside the city. It was also very dark. I tried to repair the car myself but could not find out what was wrong with the engine. By then I was completely wet. I was shivering with cold when a young man stopped his car to help.
He drove my family home first and later came back with a mechanic. He did not leave until the mechanic restarted my car and I was on my way home again. It was then that I found out I did not even know his name.
Thank you, young man, whoever and wherever you are.
Yours faithfully,
Chen Yuan
What is the purpose of Mr. Chen in writing the letter
To thank ______.

【参考答案】

a young man/a gentleman