尊敬的先生/小姐，

　　昨天收到你的来信，抱怨你新家的中央加热系统未按规定时间装好，对此我非常关心。参考较早的通信，我发现我搞错了完成日期。错误完全是我的，对此我非常抱歉。

　　认识到我们的疏忽给你造成的不便，我们将竭尽全力避免再耽搁。我已指示这项工作优先做并让工程人员加班。这样安排会于下周完成安装

邀请与答复
Invitation and Reply

Dear Mr. / Ms,

We should like to invite your Corporation to attend the 2000 International Fair which will be held from August 29 to September 4 at the above address. Full details on the Fair will be sent in a week.

We look forward to hearing from you soon, and hope that you will be able to attend.

Yours faithfully