This song is structurally beautiful and has a very unique way of drifting between two key centers, C and Eb. It starts off with a refrain over an alternation of C major, C major with a suspended fourth, and the same C major with the suspended fourth and an added flat seventh (all over a C pedal bass). After a few repetitions of this, the harmony breaks away to an Eb major seventh chord. This is then followed by Bb major, which turns out to be the dominant chord in our secondary key of Eb.
We move back then to Eb major as the tonic chord to start the verse. (This time, it's not a major seventh chord, though, as though its identity as the tonic is being grounded, whereas its tonal orientation was more ambiguous when the chord was heard just before.) Without any sense of where we might be heading, though, the chord that follows is D minor. Quickly, this is used as a ii chord, there's a ii-V-I progression, and the transition back to the home key of C is accomplished right in the middle of the second line of the verse! Very unusual.
The verse continues in C major for a bit, but then shifts to a second section that starts on an F major chord. F, of course, is the IV chord in C major, but there's a sudden shift from diatonic to blues pentatonic melodicism, and the harmonic direction from here is once again uncertain. Amazingly, the F chord turns out to be a secondary dominant (V/V) in the song's other key center of Eb, with the chords then moving from F to Ab (IV) and then Eb (I).
The Eb, however, moves once again to D minor with a repeat of the melody heard at the beginning of the verse. When we first heard that melody, of course, it sounded like an antecedent line within the lyrical structure (naturally, given that it was the first line of the verse). Here, however, it sounds like a consequent line, following after and completing the phrase begun in the two lines just before it. There's even a drum fill, as though we are reaching the end of the section.
Instead, however, that line is used just as it was the first time, as the first line of what is now the second verse, and a very unique liaison linking the two verses together is accomplished.
Amazingly, not only for a big pop smash (a number one hit in the group's home country of Australia) but for a song that genuinely sounds like a big pop smash, this song has no chorus, just repeats of that refrain in C from the beginning. The way these verses are put together, though, it doesn't need one.