21 February 1967 at EMI Studios. Producer George Martin played the prominent harpsichord part throughout because McCartney felt it important that he perform the bass part. Musical structure The song alternates between the key of F minor (in the verses) and F major (in the bridges) in basically 4/4 time. The composition is structured as follows: intro, verse, verse, bridge, verse, verse (guitar solo), bridge, verse, and outro (fadeout). The recording opens with a harpsichord playing a descending chromatic line (resembling "Michelle") in a staccato-like pattern in 4/4 time. Ringo Starr's hi-hat in the final measure of this introduction introduces a swing beat that stays for the remainder of the song. The first eight-measure verse begins with McCartney singing "I'm fixing a hole where the rain gets in". The word "fixing" here is sung to a piano F major chord but on "hole" to a C augmented chord (which includes a G/A note that is a III (3rd) note in the thus predicted F minor scale) pivoting towards the Fm pentatonic minor scale on the more negative mood of "rain gets in". The Fm key melody in the verse is tinged both by blues flat 7th, and Dorian mode raised 6th notes. The harpsichord repeats the descending chromatic line in the F minor key in swing beat. In the second half of the verse, McCartney's bass begins a syncopated three-note pattern that leaves the downbeat empty, meanwhile his vocal is dropping to F an octave below (on "stops my mind"), climbing back to C ("from wandering") then sailing free of the song's established octave to a high falsetto A flat on "where it will go". George Harrison enters in the seventh and eighth measure with a syncopated distorted Stratocaster with gain, treble and bass all turned up high, providing a distinctive countermelody, double-tracked phrase descending from McCartney's high A vocal note through what author Jonathan Gould terms a "series of biting inversions on the tonic chord". Harrison later plays an eight-bar solo that culminates in a two-octave descent. McCartney, Lennon and Harrison sing backing vocals over the bridge. The song's shift between minor (verse) and major (bridge) is also seen in "Norwegian Wood (This Bird Has Flown)" (verse E, chorus Em); "Michelle" (verse F, chorus Fm); "While My Guitar Gently Weeps" (bridge A, verse Am), "I Me Mine" (chorus A, verse Am), "The Fool on the Hill" (verse D, chorus