castles in the air
空中樓閣
書面/口語·形容空想或白日夢
英文釋義
to have unrealistic or impractical dreams or plans
例句
He's always building castles in the air, dreaming of becoming a millionaire without working.
典故來源
源自中世紀(jì)歐洲,比喻不切實際的幻想,如同在空中建造城堡一樣虛幻。