—The dictionary is a useful           for understanding new words. —I think so.

题型：不详难度：来源：

—The dictionary is a useful           for understanding new words.
—I think so.
A. secret                              B. tool                         C. way

答案

B

解析

本题表示的含义是字典是理解新单词的有用工具，tool是工具的意思，与题意相符，故本题选B。