工具书的英文：
trade book
reference book

参考例句：

They publish reference books.
他们出版工具书。

Various dictionaries and reference books are scholars' permanent friends.
各类词典、工具书，是学者们永远的朋友。

trade是什么意思：
n. 贸易；生意；交换；职业；手艺
v. 交易；对换；用…进行交换

Jack of all trades is of no trade
万事皆通,一无所长

the trade in pornography
色情作品的交易.

Foreign trade departments handle export and import trade.
外贸部门经营进出口业务。

book是什么意思：
n. 书籍；著作；圣经；有内涵的事物；知识；剧本；账簿；卷，篇
adj. 从书本上学来的；账簿记载的
v. 预订；将…的姓名记在本子上；【英】预订房间 c

subsidiary book
辅助帐簿; 明细帐簿

It was a stupid book.
那是一本无聊的书。

This is the sum of this book.
这就是这本书的要点。

reference是什么意思：
n. 提到，谈及；参考，查阅；证明人，介绍信
v. 查阅；参考；给（书）等附参考资料

The headmaster supplied him with a reference.
校长给他提供证明人。

You can refer to a dictionary if necessary.
如果有必要，你可以参考字典。

No referring back to books and notes!
不准看书和笔记！