An acoustic-guitar arpeggio opens alone, setting the pulse and the chord shape the whole song will reuse. A soft string pad gathers underneath, and the voice enters in the final bars of the span to begin the first line.

The voice moves through short, even phrases over the unchanged arpeggio; strings join around 0:12 and swell toward 0:20. Near 0:23, the opening question — 你問我愛你有多深， how deep is my love — is clearly posed, followed by the paired truth-of-love lines. The verse gathers toward the refrain boundary, where 月亮代表我的心 lands around 0:44 as the first answer.

The second verse shifts from question to recollection — the kiss that moved her, the longing lasting to this day — the same arpeggio holding the frame so the words can carry the change. Around 1:15 the refrain, 你去想一想， redirects the address outward, asking the beloved to look at the moon themselves; it lands, eases, and the strings thin in its wake.

The voice rests and the strings take the verse tune over the continuing guitar. The melody, heard twice as voice, is now proven as an instrumental line; a swell near 1:48 settles, then a gather at 2:09 relaunches the voice.

The verse comes back in its original shape — voice, arpeggio, warm pad — adding no new material and needing none. Strings swell again near 2:36, ease at 2:37, and gather at 2:43 to hand off.

The refrain returns, a section break confirming the change near 2:51, and 月亮代表我的心 is sung through again with the final syllable held long from about 3:08. The voice exits near 3:12; a last chord rings and decays into silence by 3:21.

One wheel turned twice: verse asks, refrain answers, and the interlude shows the melody carries the meaning without words.