Dear Mary,
I've received your e-mail and know that you are in a bad mood now. I am sorry to hear that you didn't do well in English exams, but I believe you will definitely do well next time. Here's some of my advice that I wish could help. You shouldn't be frustrated and can take time to figure out why you didn't do well. Maybe you need to work on your vocabularies or grammar. You can also study the exams to make sure you understand why you got some problems wrong and try not to make the same mistakes again. Failure is the mother of success. As long as you work hard and don't give up, you will succeed!
Yours,
Susan
亲爱的Mary
我收到你的email知道你现在心情不好.我很抱歉听说你英语考试没有考好,但是我相信你下次一定会考得好.这里是我的一些建议希望能帮到你.你不应该沮丧 而且能花些时间弄明白为什么你没考好. 可能你需要增强你的词汇量或者语法.你也能学习考卷确保你知道为什么有些问题错了,而且尽量不要再犯同样的错误.失败是成功之母.只要你努力学习不放弃,你就会成功.
你的,
Susan
字数比较多· 你可以按照中文意思自己删减.