I love the podcasts but it would be helpful if they were each labeled with the point in the 30-lesson series that it's appropriate to use them. Sometimes that's mentioned in the first part of the podcast, but not always, e.g. in the first podcast of level 4. I'm not sure if the first one is appropriate after the first lesson, the fourth or..... Is there a "key" somewhere that explains that, which I've missed? Oh, and the same comment applies to the audio disks supplied with the course. Thanks!