F#=Gbis an example of enharmonic equivalents
They sound the same but have different writings, so the scale of
F#major(F#C#G#D#A#E#)=Gb major(BbEbAbDbGbCb )
also have the same sounds but have different writings.
考scale 時考官會讀F# or Gb,其實彈法係一樣的
參考: Graduated from the Advanced Professional diploma in Music History and Theory(CUHK)