You can just about imagine them playing it along with the record. The lead guitar work is also faithful to the original. The refrain is eight measures long. It starts off with the same chord progression as the verse, thus somewhat blurring the musical distinction between the two sections, in spite of the fact that the harmonic rhythm is generally faster here than in the refrain. The Quarry Men don't pick up on this detail.
All sections begin with a pickup before the downbeat.
The title phrase and opening line of the lyric is unusual both for its sheer length and its manner of leading off which a grammatical subordinate clause. Paul's backing alternates between harmonizing with John in close but standard harmony, and short obbligato licks. The intro is just two measures long but the downbeat is preceded by a guitar pickup that nearly anticipates the jumpiness of the vocal line without actually giving it away. I V Verse - The verse is eight measures. The harmonic shape is closed at both ends.