build castles in the air
白日做梦、空中楼阁
口语·形容不切实际的幻想
英文释义
to have unrealistic or impractical dreams or plans
例句
He keeps building castles in the air about becoming a millionaire without doing any real work.
典故来源
源自17世纪英国作家约翰·班扬的《天路历程》，比喻不切实际的幻想，如同在空中建造城堡般虚幻。