出典:Wiktionary
The phrase is originally from the song “The Preacher and the Slave” (1911) by Swedish-American labor activist and songwriter Joe Hill (1879–1915), which he wrote as a parody of the Salvation Army hymn “In the Sweet By-and-By” (published 1868). The song criticizes the Salvation Army for focusing on people’s salvation rather than on their material needs:[1]
pie in the sky (uncountable)
the sky at daybreak
大空.
the stratosphere
the upper reaches of the sky
the blue sky above
青空.
the blue sky
the blue sky