★ 风格：两篇写作，１篇是正式，１篇是非正式。
★ 体裁：
短篇：memo, note, email
长篇：fax, proposal , letter（诉信、道歉信、邀请信、询价信、感谢信等）, report （report on...、introduction、findings、conclusions、recommendations前面四个一个也不能少，至于最后的recommendations要看当时的题目要求）
（二）要 求
the purpose of the correspondence
references to previous communication
factual details
the feelings and attitude of the writer
the level of formality
the opening sentence
the closing sentence
paragraphing
the desired outcome
