
Re-reading a whole set of lecture notes the night before an exam is the slow way to review. Marking the notes as you go, then boiling each section down to a summary, is faster and sticks better.
FlexFiles PDF Editor does the marking and summarizing in one file, in your browser.
One color for definitions, another for examples, a third for anything you're still unsure about. Consistency across a whole course matters more than which colors you pick.
A page of notes with the important parts marked reviews faster than a page you have to read cold. FlexFiles makes the marking free and quick, with nothing to install.