half a day=a half day,那为什么half a dozen 却没有a half dozen 这种说法?

half a dozen在这里是什么意思 half a day 为何不说half day.类比half apple a half/half a "six of one and half a dozen of the other? "six of one and half a dozen of the other half a day 为何不说a half day 半斤八两be six of one and half a dozen of the other dozen one and a half day /one and a half days half a he often___(relax) half a day 有half a year 的说法,那有没有a half year 的说发? 英语翻译Also listening to her were a half a dozen other family m