two items of the same kind
同义词：couple??/??pair??/??twosome??/??twain??/??brace??/??span??/??yoke??/??couplet??/??duo??/??duet??/??dyad??/??duad
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。