一打，12个(set or group of twelve) [C]：sell eggs/eat cookies by the～论打卖鸡蛋/吃饼干; sell/pack eggs in～s 按打卖/包装鸡蛋;Eggs are 60p a～. 鸡蛋60便士一打。How many eggs are there in four～? 四打鸡蛋有多少个? a～or so 一打左右;a～and a half (one and a half～) 一打半;half a～times/languages 六次/六种语言;half a～handkerchiefs/socks 半打手帕/袜子;a～people 12个人;a～roses/oranges 一打玫瑰花/橘子; two～copies 24份;several～sheets (of paper)几十张(纸);I need two～more. 我还要两打。a baker's～13个;six of one and half a～of the other 半斤八两(彼此彼此);

dozens of 许多(infml)：D～s of children/them were there. 许多孩子/他们中许多人在那里。“Have you got many records?”“ Yes. D～s.”“你有许多唱片吗? ”“对，很多。”

talk/speak/chat，etc nineteen to the dozen 说个不停(infml)：The people were talking nineteen to the～. 那些人在没完没了地高谈阔论。

【惯用法】dozen用来计量买卖中不以重量计量的商品(如鸡蛋、玫瑰花等)，如：two～eggs(两打鸡蛋)。注意，用于数词后表示计量时，其复数形式与单数形式相同。a dozen of 仅用于特指某种东西(名词前有指示代词或物主代词)时，如：a～of those red roses/your eggs(一打那种红色的玫瑰花/你的鸡蛋)，或其后为代词时，如：a～of them(他们中的12人);一般不说 a～of roses，而说a～roses。