downcast shaft
collocation进风井；下行通风井
Fresh air travels down the downcast shaft into the mine.
新鲜空气沿着进风井下行进入矿井。
向下转换；向下转型
downcasts — plural of downcast
先理解核心含义，再看它在真实句子里的用法。
向下转换；向下转型
In computing, a cast that converts a value from a supertype to a subtype; a downcast.
The miners entered the mine through the downcast to access the lower levels.
矿工们通过进风井进入矿井，到达下层工作面。
编程术语
向下看的动作,通常表示沮丧、悲伤,有时表示谦逊；引申为沮丧、忧郁
An act of looking downwards, usually as a sign of discouragement, sadness, etc., or sometimes modesty; hence (uncountable, archaic), dejection, melancholy.
进风井
a ventilation shaft through which air enters a mine
(数据类型)从父类型到子类型的转换
A cast (“change of expression of a data type”) from supertype to subtype.
矿井中空气下行通风的通风井
A ventilating shaft down which air passes in circulating through a mine.
Fresh air flows down the downcast, providing ventilation to the underground tunnels.
新鲜空气沿进风井流入，为地下巷道提供通风。
The engineer inspected the downcast for any blockages that could reduce airflow.
工程师检查了进风井是否有堵塞，以免影响气流。
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进风井；下行通风井
Fresh air travels down the downcast shaft into the mine.
新鲜空气沿着进风井下行进入矿井。
低垂的目光
The downcast of her eyes revealed her modesty.
她低垂的目光流露出她的谦逊。
显式向下转换
The compiler rejected the code because it required an explicit downcast.
编译器拒绝了这段代码，因为它需要显式向下转换。
Use downcasts naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
把“cast”（投射）想象成目光向下投：眼睛朝下看，自然显得沮丧或谦卑——记住“down（向下）+ cast（投射）”就是垂头丧气的样子。
语域：mixed 常见场景：文学/正式写作、采矿工程、编程/软件开发 含义因语境而异：采矿工程中指“进风井”，编程中指“从父类型到子类型的向下转换”；而“低头/沮丧”的用法比较正式，多用于文学或书面语。
该词作为可数名词，指矿井中的进风井。
Dictionary facts from ECDICT, WIKTIONARY.