Hello, thanks for posting!
If you have trouble viewing the characters in the original Lesson Notes PDF, please try opening the Lesson Notes LITE PDF (it also comes with every lesson):
http://www.koreanclass101.com/pdfs/S_S1 ... bedded.pdf
This version of the PDF uses different fonts, and we find that a lot of our Mac users who can't correctly view the original have better luck using these.
Please let us know if that helps