南柯一梦的英文：
[Literal Meaning]
south/branch/a/dream
the Dream of Southern Branch

[解释]
比喻一场空欢喜。

[Explanation]
This is an allusion to illusory joy.

[例子]
韩亮想去美国发大财的想法最终仅仅是南柯一梦，花光了所有的钱后他也没有找到任何工作。

[Example]
Han Liang's idea of going to the US to make his fortune was proved to be only a fond dream. After he spent all his money, he found no job.

[英文等价词]
a pipe dream

a fond dream or illusory joy
南柯一梦