【正确答案】[参考范文]
Dear Johnson,
I got the news from Mike that you have received a Doctorate in Physics from Harvard University. I congratulate you for this. To have reached this milestone in your scholarship at a young age is really great. It means, I believe, years of assiduous study and hard work on your part. And it is an achievement you can be well proud of. As your best friend, I hope you can reach higher level in your study and do more contribution to the society. My best wishes to you!
Sincerely,
Wang Ling