我告诉你妈妈我在写这封信，问她有什么想对你说的。

I told your mom I'm writing this letter, and asked what she wanted me to say.

youdao

这封信明显是在匆忙中写的。

The letter had clearly been written in haste.

《牛津词典》

我写这封信是为了申请作为在贵美术馆举办的中国绘画展览的志愿者。

I am writing to apply for a volunteer of the Chinese Painting Exhibition to be held in your art gallery.

youdao