Can someone explain to me what is going on tonally in Beyonce's song Blow? The bass notes deceptively seem to suggest the chords in the verse are G major and F major. But these chords do not sound right. It seems that the actual chords are FM7/G and EbM7/F. And then later in the song there is a C to D7, which suggests to me that the song is in G major, But then I don't understand how FM7/G and EbM7/F are fitting into this key?
I am used to understanding chord progressions as degrees in a key/scale (for example I'm Yours by Jason Mraz is I, V, vi, IV in B Ionian). I cannot wrap my head about what is going on in Blow in terms of key/mode! Any insight is much appreciated.