(Modifier +) 书
The noun 书 (shū) most commonly means "book," but in formal and legal contexts it can mean "document" or "written agreement." In the compound 议定书 (protocol), 书 refers to a formal written document. It is one of the most fundamental and versatile nouns in Chinese.
我最近在看一本关于中国历史的书。
Wǒ zuìjìn zài kàn yī běn guānyú Zhōngguó lìshǐ de shū.
I've been reading a book about Chinese history recently.
这份议定书是两国合作的重要文件。
Zhè fèn yìdìngshū shì liǎng guó hézuò de zhòngyào wénjiàn.
This protocol is an important document for bilateral cooperation.
他每个月都会读好几本书。
Tā měi gè yuè dōu huì dú hǎo jǐ běn shū.
He reads several books every month.