Your letter; Your favour; your esteemed letter; Your esteemed favour; Your valued letter; Your valued favour; Your note; Your communication; Your greatly esteemed letter; Your very friendly note; Your friendly advice; Yours.
Our (my) letter; Our (my) respects; Ours (mine); This letter; these lines; The present.
The last letter; The last mail; The last post; the last communication; The last respects（自己的信）; The last favour（來信）
The next letter; The next mail; The next communication; The letter following; the following.
Your letter of (the) 5th May; Your favour dated (the) 5th June; Yours of the 3rd July; Yours under date (of) the 5th July; Your letter bearing date 5th July; Your favour of even date(AE); Your letter of yesterday; Your favour of yesterday's date; Your letter dated yesterday.
Your telegram; Your wire; Your cablegram（從國外）; Your coded wire（口令電報）; Your code message; Your cipher telegram; Your wireless telegram; Your TELEX; Your Fax.
Your telephone message; Your phone message; Your telephonic communication; Your telephone call; Your ring.
Advice; Notice; Information; Notification; Communication; A report; News; Intelligence; Message.
To communicate (a fact) to; To report (a fact) to...on; To apprise (a person) of; To let (a person) know; To acquaint (a person) with; To intimate (a fact) to; To send word; to send a message; To mail a notice; to write (a person) information; To give notice（預告）; To break a news to（通知壞消息）; To announce（宣佈）.
An answer; A reply; A response.
To answer; To reply; To give a reply; To give one's answer; To make an answer; To send an answer; To write in reply; To answer one's letter.
Reply to; Answering to; In answer to; In reply to; In response to.
To await an answer; To wait for an answer.
To get an answer; To favour one with an answer; To get a letter answered.
Receipt（收到）; A receipt（收據）; A receiver（領取人，取款人）; A recipient（收款人）
To receive; To be in receipt of; To be to (at) hand; To come to hand; To be in possesion of; To be favoured with; To get; To have; To have before (a person); To make out a receipt（開出收據）; To acknowledge receipt（告知收訖）.
To confirm; Confirming; Confirmation; In Confirmation of（為確認...,為證實...）; A letter of confirmation（確認函或確認書）
To have the pleasure to do; To have the pleasure of doing; To have pleasure to do; to have pleasure in (of) doing; To take (a) pleasure in doing (something); To take pleasure in doing (something); To be pleased to (with)(by); to be delighted at (in)(with); To be glad to (of)(about); To be rejoiced in (at).
Urgently; Promptly; Immediately; With all speed; At once; With dispatch; With all despatch; With the quickest possible despatch; With the least possible delay; As soon as possible; As quickly as possible; As promptly as possible; At one's earliest convenience; At the earliest possible moment; At an early date; Without delay; Without loss of time; Immediately on receipt of this letter; By express messenger; By Special messenger; By special delivery; By express letter.
By return; By return of post; By return of mail; By return of air-mail.
According to; Agreeably to; Conformably to; pursuant to; In accordance with; In conformity with (to); In obedience to; In deference to; In compliance with; In agreement with; In pursuance of.
About; Regarding; Concerning; As to; As regards; With regard to; In regard to;(of); Respecting; Relative to; Anent; In connection with; Referring to; With reference to; In reference to; Re.
To be due; To fall due (become) due（日期將到）; Duly（正時，及時）；In due Course （依照順序）.
Per(=by, through) rail.(post,mail,steamer)（通過鐵路，郵政，輪船）
Per pro.= by proxy （由代理）
Per annum （=yearly，每年）
Per mensem (=monthly,每月)
Per diem [daiem] (=daily,每日)
Per man, per capital (=per head,依照人數，每一人）
Per piece （每一個，每一件）
To take the liberty of doing something; To take the liberty to do something; To take the liberty in doing something.
To regret; To be sorry; To be chagrined; To be mortified; To be vexed; To regret to say; To be sorry to say; To one's regret; To feel a great regret for; To express regret; To be regretted; To be a matter for regret; To be regrettable; To be deplorable.
To have the honour of doing (being); To have the honour to do (be); To do one (oneself) the honour of doing (being); To esteem (regard) it as a high honour to do (be); To appreciate the honour to do (be); To feel honoured to do (be); To owe one a debt of honour to do (be); To be honoured with doing (being) something; To honour one with doing (being) something.
Please; Kindly; be good enough; Be kind enough; Have the kindness.
To thank; To be (feel) thankful; To be (feel) grateful; To be obliged; To be indebted; To esteem (it) a favour (privilege); To give (tender, return) one's thanks; To express one's gratitude (appreciation); To tender one's sincere thanks for; To be overwhelmed with gratitude.
Command; Order; Service
To command; To order; To serve; To be at one's service; To render service to one; To do one a service; To be of service to one