七大原则： 
一、Courtesy 礼貌 
语言要有礼且谦虚，及时地回信也是礼貌的表现。 
例如： 
We have 
received with many thanks your letter of 20 May, and we take the pleasure of 
sending you our latest catalog. We wish to draw your attention to a special 
offer which we have made in it. 
You will be particularly interested in 
a special offer on page 5 of the latest catalog enclosed, which you requested in 
your letter of 20 May. 

二、Consideration 
体谅 
写信时要处处从对方的角度去考虑有什么需求，而不是从自身出发，语气上更尊重对方。 
例如： 
“You 
earn 2 percent discount when you pay cash. We will send you the brochure next 
month. ”就比 “We allow 2 percent discount for cash payment. We won't be able to 
send you the brochure this month.” 要好。 

三、Completeness 
完整 
一封商业信函应概况了各项必需的事项，如邀请信应说明时间、地点等，确忌寄出含糊不清的信件。 

四、Clarity 
清楚 
意思表达明确，要注意： 
(一)避免用词错误： 
例如：As to the steamers 
sailing from Hong Kong to San Francisco, we have bimonthly direct 
services. 
此处bimonthly有歧义：可以是twice a month 或者once two 
month.故读信者就迷惑了，可以改写为： 
1.We have two direct sailings every month from 
Hong Kong to San Francisco. 
2.We have semimonthly direct sailing from 
Hong Kong to San Francisco. 
3.We have a direct sailing from Hong Kong 
to San Francisco. 
(二)注意词语所放的位置： 
例如： 
1. We shall be 
able to supply 10 cases of the item only. 
2. We shall be able to supply 
10 cases only of the 
item. 
前者则有两种商品以上的含义。 
(三)注意句子的结构： 
例如： 
1.We 
sent you 5 samples yesterday of the goods which you requested in your letter of 
May 20 by air. 
2.We sent you, by air, 5 samples of the goods which you 
requested in your letter of May 20. 

五、Conciseness 
简洁 
(一)避免废话连篇： 
例如： 
1.We wish to acknowledge receipt of 
your letter...可改为：We appreciate your letter... 
2.Enclosed herewith 
please find two copies of...可改为: We enclose two copies 
of... 
(二)避免不必要的重复： 
(三)短句、单词的运用： 
Enclosed 
herewith----->enclosed 
at this time----->now 
due to the 
fact that----->because 
a draft in the amount of $1000----->a 
draft for $1000 
六、Concreteness 具体 
七、Correctness 正确