(1) 前四个短语都是“关于”，相当于about, concerning，常用于公函中。

• With/In reference to your letter of the 8th. inst. (instant的缩写)， we have to inform you that the cost of doing the repairs would be $3,000.
  关于你本月8日的来信，我们不得不告诉你维修费将达到3000美元。
• I'm writing to you with/in reference to the repairs recently carried out at the above address.
  我写信给你，是关于最近在以上地点所进行的维修事宜。
• I have nothing to say with reference to this matter.
  关于这件事，我无话可说。

 (2) with/in regard to, as regards意为“关于，至于”，作“至于”解时，常用于引出另一话题。

• As regards/In regard to/With regard to the contract, the second paragraph should be changed.
  至于合同，第二段应修改一下。
• You needn't worry as regards the tuition. the Party and the state will certainly take your difficulties into full account.
  至于学费你无须忧虑，党和国家肯定会充分考虑到你的困难。

 (3) in answer to, in reply to意为“作为对……的回答；响应……”。

• Frank came to my office at once in answer to my telephone call.
  一接到我的电话，弗兰克马上就来到我的办公室。
• She wrote a warm letter of thanks in reply to our message of invitation.
  她写了一封热情洋溢的感谢信回复我们的邀请。
• He volunteered to go and work in Tibet in answer to the call.
  为响应这次号召，他自愿前去西藏工作。
• In answer to your fax of the 10th. inst., we've to tell you that you must make an offer of reduction in the price before any further cooperation between us is considered.
  为回复你本月10号的传真，我们必须告诉你，在考虑我们双方的进一步合作之前，你必须在报盘中降低价格。

 (4) 现在英美商业函电中，多已不用这些短语，而改用其他说法。

• We have had the pleasure of receiving your letter of 8th. this month.
  收到你本月8号的来信，我们不胜荣幸。
• Thank you very much for your letter of the 8th. this month.
  非常感谢你本月8号的来信。