“six feet under”别理解成“在六英尺之下”，其正确的含义是入土，死去。

【例句】
There's no point worrying about it - we'll both be six feet under by then.
不用为此担心——到时候我们俩都已入土了。

She wanted her daughter to inherit her business when she would be six feet under.
她希望自己百年之后，女儿可以继承她的生意。