To have unrealistic or impractical plans or dreams.
非現実的または不実用的な計画や夢を持つこと。 (Higenjitsuteki matawa fujitsuyōteki na keikaku ya yume o motsu koto.)
"She’s always building castles in the air, dreaming of a perfect world."
"彼女はいつも空中に城を建てている、完璧な世界を夢見ている。" (Kanojo wa itsumo **kūchū ni shiro o tatete iru**, kanpeki na sekai o yumemite iru.)
something that is visually appealing but may lack substance...
to work extremely hard
not tell anyone about something
to earn enough money to live on
to take a break or stop what you are doing temporarily
the most advanced or innovative
