A book drop is the small metal door in the wall of the building where people can return books when the library is closed.

VOA: special.2009.02.23

Please make sure you drop your library card at the front desk before you leave.

请确保在离开时，把图书卡放在前台。

have to 实战 - SpeakingMax英语口语达人

Please make sure you drop your library card at the front desk before you leave.

请确保在离开时，把图书卡放在前台。

have to 实战 - SpeakingMax英语口语达人