by the hour是什么意思

英語有些詞“單位詞”，如hour, day, month, year, dozen, gallon, ton, yard等，當它們表示標準含有類似漢語的“按”“論”“每”等義時，其前原則上要用定冠詞。如：

They let out cars by the day. 他們按天出租汽車。

The cloth is sold by the yard. 這種布是按碼賣的。

They are paid by the hour. 他們所得報酬按小時計。

Do you sell eggs by the kilo or by the dozen? 雞蛋怎么賣，論公斤，還是論打?

Is gasoline sold by the gallon in America? 在美國，汽油是以加侖出售的嗎?

但是，by weight(按重量)習慣上不用冠詞。如：

Bananas are usually sold by weight. 香蕉通常按重量賣。