● 認為對方收到了自己的信件

幾個月前，我們曾就……事給您寫了一封信。
Some months ago we wrote you regarding... *regarding “關于……”。

就……事我們至今沒有得到您的回音。
So far, we do not seem to have received word from you... *催促什么事情時。

如果在1998年12月1日前還得不到您的回音的話，……
If we do not hear from you by December 1, 1998...*語氣有些嚴厲。

有關……事，我們還未收到您的任何回音。
So far, we have not received word from you... *so far “至今為止”。
So far, we have not received any word from you...

● 因回復遲了而表示歉意

很抱歉未能盡早給您回信。
We apologize for not replying to you earlier.

未能及時給您回信，我們深表歉意。
We are sorry for not answering your letter sooner.
We are sorry for not replying to your letter sooner.
We are sorry for not responding to your letter sooner.

久未回信，讓您久等了。
Thank you for your patience. *patience “忍耐，耐心，耐性”。?