The verse here is four lines. When the fifth line of text begins, we seem to have switched to a new section. As it's too early for a bridge, this appears to be an exploratory extension of the verse. Amazingly, though, this cuts off after two lines and instead of getting another two lines with a rhyme for line two at the end of line four, we get the song's chorus instead, itself two lines long (and rhyming, for the first time, line-by-line).
Macro-structure (arrangement, too) is worthy not just of McCartney, but of McCartney at his best. Verse, chorus, verse, chorus, and then a bridge. Back for one final verse/chorus and then the bridge again, this time with a variant on the text and, with one added line bringing harmonic resolution, used as a closing.
That's a pretty concise structure, but this thing is 3:05 and reached number fifteen on the singles chart.*
* Worth pointing out that three of Bread's big hits actually do have a very short duration: "It Don't Matter to Me" (2:41), "If" (2:33), and "Baby I'm-a Want You" (2:25!).