Is all Supplementary mentioned in the lesson audio?

Are all the supplementary vocab words mentioned in the lesson audio (not just the dialogue) ? Or are they just there for extra words for helping to understand? Because I often can’t hear the supplementary words during the audio for the lesson. Has it been consistent for the older lessons across different levels as well, for example the lessons in 2007?

Some of the supplementary vocabulary are used in the Expansion section, not all. Supplementary vocabulary is often not used in the lesson itself. They are ‘supplementary.’ Varies, I’ve noticed, from lesson to lesson.