【正文】 see, it greatly threatens the reader’s negative face. On the contrary, sentence (19) chooses a longer plex sentence which can distract the reader’s attention from the bad news. What’s more, the main clause gives out the reason for the reader to accept the cost. To sum up, longer plex sentences help convey the unpleasant message in an indirect way, which helps weaken the face threat to the reader. Using longer plex sentence can maintain the friendly relationship. Politeness in persuasive business letters Persuasive letters aim to influence the reader to accept the writer’s points (尹小芳，2001:410). Therefore, if the views are presented directly, the reader will not accept it. Thus, to make the persuasion more effective and more acceptable, indirect approach is often used in persuasive business letter. In order to achieve goals, it is better for the writer to use more youlanguage instead of “I” or “we”, which shows the writer’s interest.Usually, the politeness in persuasive business letters can be divided into four steps: 1) Attention, 2) Interest, 3) Conviction, 4) Action. AAttentionAAttention means to draw the reader’s attention as quickly as possible, the writer should find out what the reader may be interested in (鄭衛(wèi)，2002:420). However, the letter may be considered totally useless or even bothering the reader. Therefore, it is better to use the shortest time to attract the reader’s attention. At the beginning of the letter, it is better for the writer to present a point that the reader can agree with. According to Brown and Levinson (1987:300), this helps attending to the reader’s positive face. Most importantly, it may maximize the agreement and sympathy between the writer and the reader. IInterestOnce having attracted the reader’s attention, the writer should take a further step to arouse the reader’s interest. In this part, the writer introduces the idea that may bring benefits or avoid a loss to the reader. According to the Tact Maxim and Generosity Maxim, the writer should emphasize the benefits and deemphasize the cost. The ideas must meet the reader’s need and desire, thus attends to the results positive face. CConvictionConviction means the writer should try to convince the reader and take the reader’s request (鄭衛(wèi)，2002:420). Conviction is the most important part of the whole letter. In fact, as a writer of a persuasive business letter, he or she has made a choice for the reader. The point is how to make the reader believe the writer’s choice is the best for the reader. Therefore, in the processes of persuasion, the writer should emphasize the facts that show the writer’s choice benefits the reader. By this way, the reader is more likely to accept the request. AActionIn this part, the writer gives the reader a push to accept the writer’s request (鄭衛(wèi)，2002:430). There will be a cost to the reader, thus will threaten the reader’s negative face. Therefore, in this part, proper techniques should be chose to soften the potential face threatening. For example, when the idea need a major change and mitment on the part of the reader, we should persuade the reader to take small steps rather than ask for a major mitment all at once. of politeness principle in English business lettersFrom the previous analysis, it can be found that each type of business letter is different from others in its nature concerning politeness. Therefore, the functions of politeness in different English business letters are different according to their different types of letters. Maximizing the facebuilding effects of the good newsGenerally speaking, goodnews business letter is beneficial to maintain the reader’s face, so this type of letter is to maximize the facebuilding effect of the good news. Direct express is used in order to make the reader understand clearly and quickly. In a good news business letters, deductive approach is often adopted to make the good news more direct to the reader. Short sentences, active voice and affirmative structures also help convey the favorable news in the most efficient way. Specific words and the “you” language also strengthen the favorable effect of the good news. All the abovementioned techniques highlight the benefits to the reader and attend to the reader’s face want, making the letter more tactful and more polite. the facebuilding effects of the bad newsOn the contrary to goodnews business letter, badnews business letter threatens the reader’s positive face, thus is impolite in nature. This type of business letter is to minimize the facethreatening effects of unfavorable messages. Therefore, in badnews business correspondence, indirectness is the most distinct linguistic feature for consideration of politeness. Moreover, longer sentences with plex structures, interrogative sentences, subjective mood, positive statements and passive voice also can be used to weaken the negative effect of the bad news. Concerning the words and expressions, it is better to avoid suspicious structures and youlanguage when referring to impolite messages. Using general words, neutral words, noun phrases, modal auxiliaries and hedges also help soften the face threatening force of the unfavorable messages. the degree of imposition of the persuasive。 (2) be polite, as Pragmatic Competence. She also proposes three maxims of politeness from the perspective of the speaker.1) Don’t imposeUsed when formal/ impersonal politeness is required2) Give optionsUsed when informal politeness is required3) Make H feel goodUsed when intimate politeness is required (Lakoff, 1973:300)From Lakoff’s opinion, the speaker should avoid putting any imposition on the hearer, and choose to give the hearer options, in order to keep his positive face. At last, “make the hearer feel good” is very important (Lakoff, 1973:300). Lakoff’s view of politeness is in accordance with the politeness concerns