算盘
Around the year 1200, the Chinese refined the design, creating suan-pan, or the modern, wire-based abacus.
FORBES: No. 2 The Abacus
英汉双解词典包含3185865条英汉词条,基本涵盖了全部常用单词的翻译及用法,是英语学习的有利工具。