【答案解析】Dear Linda,
I am writing to you to express my warm congratulations on
[1]
your winning a full scholarship from Stanford University for a further study.
Actually, I am not surprised at all to hear your good news because I know what and how you have done to make your dream come true.
[2]
Being an ambitious person, you have always been eager for a further study as a postgraduate in a prestigious university. In order to realize your dream, you have shown both diligence and persistence in your study in the past four years of school life, which has finally been rewarded
[3]
in this way. It makes me firmly believe in the proverb—no pains, no gains.
[4]
After all, your excellent performance indeed deserves that. I am pleased to say that what is right ahead of you is a promising future.
[5]
Congratulations again. I wish you all the best in your future life and study.
Yours sincerely,
Li Ming
[解析] [1]名词短语congratulations on意思是“祝贺；恭喜”，也可用缩略形式congrats on，这是表达祝贺的常用表达方法。
[2]第二段首句为本段主题句，统领全段内容。后面内容对其进一步阐释吗，结构清晰。其中ambitious、diligence和persistence三个词的使用，展现出了Linda所具备的成功者的品质和付出的努力。句中的原因状语从句中又包含一个宾语从句what and how you have done...，不仅起到承上启下的作用，而且增加了句式的灵活性。
[3] 采用了which引导的非限制性定语从句，表明Linda的勤奋努力终于得到了回报。
[4] 破折号后的谚语no pains, no gains意为“一分耕耘，一分收获”，与前文的内容相呼应，句子之间衔接紧凑，自然流。
[5] a promising future意为“有前途的未来”，这里的promising可以替换为rosy、favorable、bright等形容词。