Continue with the body of the letter, stating your main purpose for writing.

继续写信函的正文内容，以你写信的目的为开头。

youdao

For my own purpose — writing philosophical prose — I felt that explicitly numbered section levels were better.

出于我自己的目的考虑——编写哲学散文——我觉得明确编号的节级别更好一些。

youdao

This allows developers to easily interchange services as needed without writing tedious code for the sole purpose of making them work together.

这样就允许开发者在需要时很容易地互换服务，不需要再编写那些唯一的目的就是使这些服务能协同工作的累赘的代码。

youdao

Historians say that by writing the Emancipation Proclamation, Lincoln established a moral purpose for the war.

VOA: special.2009.02.09