英语书信的形式与商务书信的写作 forms of english letters and writing of business letters
事务书信的撰写技巧 b. business letters for social sciences students: objectives and techniques
商务书信与私人书信的不同点 br / differences between business letters and private letters
书信 letter; written message 书信格式 form of a letter; 商业书信 business correspondence; 和 ...书信不断 be in constant correspondence with ...; 包裹内不得夹带书信。 the package carries no written message