missive|missives

他写了一封长达八页的信，详细描述了他的新办公室。

He wrote an eight-page ___missive describing his new office in detail.

他每天都会收到来自公司总部的长篇公函。

He receives lengthy ___missives from the headquarters every day.

校长收到了一封来自教育部的正式公函。

The principal received an official ___missive from the Ministry of Education.