1. 信件的开头：
We are writing to enquire about...
We are writing in connection with...
We are interested in ... and we would like to know...
环境：
You want to know the prices of some air conditioners.
We are interested in your air conditioner and we would like to know the prices of some air conditioners.
You saw an advertisement in the newspaper yesterday and you want further information.
We are writing in connection with the advertisement in the newspaper yesterday.
You want to know if the company you are writing to organizes holidays to Africa.
We are writing to inquire about the holidays to Africa that your company organizes.
2. 回信的开头：
Thank you for your letter of (date)
We have received your letter of (date) asking if ...
enquiring about ...
enclosing ...
concerning ...
环境：
A company wrote to you on 23 July. They wanted to know if you sell photocopiers.
Thank you for your letter of 23 July, asking if we sell photocopiers.
A man wrote to you on 18 December. He wanted employment with your company. He also sent his curriculum vitae.
We have received your letter of 18 December, enclosing your curriculum vitae.
A company sent you a fax on 3 June. They wanted to know if you were going to the marketing conference in London.
Thank you for your fax of 3 June, asking if I was going to the marketing conference in London.
A woman telephoned you this morning. She wanted to know if her order No. 599 had arrived.
Thank you for your telephone call this morning concerning the order No. 599.
3. 信件的结尾：
一般结尾：
I look forward to receiving your reply/order/products/ect.
Looking forward to hearing from you.
如果你在信件中提供了信息：
I hope that this information will help you.
Please contact me if you need any further information.
Please feel free to contact me if you have any further questions.
Please let me know if you need any further information.
4. 引入主题：
With reference to ...
Further to ...
With regard to ...
I am writing in connection with ...
注：引入主题的句子可以被写在信件的开头，但with regard to 不能用于信件的开头。
环境：
(How would you start a letter about each of the following?)
an invoice (No. 679) for a photocopier
With reference to Invoice No. 679, we regret to tell you that the product arrived in bad condition.
a meeting you had with the addressee on Jan. 16th
Further to the meeting on 16 January, I am delighted to tell you that we are now able to give you a special offer for our Peach Series computer.
an advertisement in the times newspaper
I am writing in connection with the advertisement in the times newspaper yesterday.
an application for a post as secretary in your company
I am writing in connection with your application for a post as secretary in our company.
a fax order for six computers that you received today
with reference to your fax order for six computer, I regret to tell you that they are out of stock at present.