Dear Mr. Sun,

It is a great pleasure to send you my sincere congratulations on the 60th anniversary of Phoenix Trading Company.

We consider it our good fortune to have had you as a customer for at least 25 years. It is common knowledge that your company is one of the most respected firms in the industry. It has made steady progress and growth over the past decades.

We wish you every success in the future and look forward to a continuing pleasant relationship with your company.

With all the best wishes,

Carl Terry

Analysis

Sample 1和Sample 2是两封简短而正式的贺信。开门见山，第一段就表示祝贺并说明祝贺事由；第二段进行积极评价；结尾表达对未来的祝愿。两封信措辞热情、喜悦、真诚。