1) 请对方来发表一个speech，这封信是要感谢对方，同时确认对方对技术设备的具体要求。
dear sir/madam,im delighted you have accepted our invitation to speak at the conference in [city] on[date].
as we agreed, youll be speaking on the topicfrom [time] to [time]. there will be some time for questions.
would you please tell me what kind of audio-visual equipment youll need? if youcould let me know your specific requirements by [date], ill have plenty of time to make sure that the hotel provides you with what you need.
thank you again for agreeing to speak. i look forward to hearing from you. sincerely yours,
[name]
[title]
2) 这封信则是请对方来参加自己公司的一个招待会。
dear sir/madam,
thank you for your letter of [date]. im glad that you are also going to [place] next month. it would be a great pleasure to meet you at the [exhibition/trade fair].i look forward to hearing from you soon.
yours sincerely,
[name]
[title]
3) 邀请收信人参加自己公司的产品演示会。
dear sir/madam,
we would like to invite you to an exclusive presentation of our new [product] presentation will take place at [location], at [time] on [date]. there will also be a reception at [time]. we hope you and your colleagues will be able to look forward to seeing you on [date]. just call our office at [phone number] and we will be glad to secure a place for you.
sincerely yours,
[name]
[title]