these four walls 字面意思是“这四面围墙”，其实在口语中是用于叮嘱保守秘密，即“打住，到此为止”。
【例句】
【例句】
Don't let this go further than these four walls.
走出这屋就不要再谈这事了。
These four walls also as structure bulkheads for the hull!
这些四面墙壁也充当结构的舱壁为船体!
These four walls also as structure bulkheads for the hull!
这些四面墙壁也充当结构的舱壁为船体!
