Use a PDF reader that supports "Reflow" mode (like Adobe Acrobat mobile). This strips the layout and makes the text flow like a webpage. Alternatively, buy a cheap 10-inch tablet (Amazon Fire HD is fine) specifically for PDFs.
: Covers -거든요 (because), -느라고 (due to doing something), and -는 바람에 (due to an unexpected event). korean grammar in use intermediate pdf
Here's a sample text related to Korean grammar at the intermediate level: Use a PDF reader that supports "Reflow" mode