two dozen of them 它们中的两打
three scores of these eggs 这些鸡蛋中的三打
five hundred of the workers 这些工人中的五百人
5. 注意以下与介词 by 连用的例子(from www.hxen.com)：
The eggs are sold by the dozen. 鸡蛋按打出售。
The ants arrived at the picnic by the hundred(s). 成群的蚂蚁来到野餐的地方。
They were sold by the thousand(s). 它们被大批大批地(论千地)出售。
比较：Pack them in dozens. 把它们成打地包起来(即每12个一包)。