A pipe dream 白日梦

一个人即使计划得再好，如果没有切实可行的条件，那梦想就如同烟雾一般虚无飘渺。我们通常使用英语表达“a pipe dream”来指出某人的计划或想法“如同白日做梦一般，行不通”。这个说法有消极意味，所以不能用来描述 “梦想、美梦”等相对积极的概念。

例句

My mother says my father’s plan to sail around the world in his retirement is just a pipe dream.
我母亲说，父亲想要在退休后扬帆出海、环游世界的计划只是白日做梦。

The marketing manager is very confident and insists that her plan to increase company sales by 150% is not a pipe dream.
市场部经理坚信她计划提升公司销售额150%的方案不是空想。

My brother’s laziness is evidence that his dream of becoming a successful entrepreneur is just a pipe dream.
我弟弟的懒惰足以证明，他想要成为成功企业家的黄粱美梦是行不通的。