Question:

　　Dear Ms.abc,

　　你好，我想请教一下，我现在正在向客户发广告信件，请问在一开始如何用英文表达：我很抱歉打扰您，感谢您在百忙之中阅读我的信件。

　　谢谢！

　　njxffy

　　Answer:

　　Dear njxffy,

　　you could express " Sorry to interrupt you by sending this letter to you and really thanks for your taking time reading it"

　　Yours abc