在高考英语作文中，介绍信的开头部分应该简洁明了，同时能够吸引读者的注意。以下是一些高级开头的示例：

表达兴趣或目的

I am writing to introduce myself and express my interest in [topic of interest].

I am writing to introduce my friend/colleague, who is interested in [topic of interest].

直接介绍

I am writing to introduce [name of the person], who is [a brief description of the person].

I am writing to introduce Mr./Ms. [last name], a [title/position] at [organization/institution].

提供背景信息

With great pleasure, I am writing to introduce [name of the person], who is currently [current situation or activity].

It is my honor to introduce [name of the person], who is [a notable achievement or status].

表达感谢或期待

I am writing to thank you for considering my introduction and to express my eagerness for [next steps or outcome].

I am writing to introduce [name of the person] and look forward to the opportunity to work together.

这些开头方式可以根据具体情境和需要进行选择和调整，以确保介绍信的开头既礼貌又具有吸引力。