Lessons

Every other mode on this site — decks, exams, labs, coding — tests what you already met somewhere else. That works when you arrive with prior exposure. It does not work for a domain that is new to you. A lesson is where the concept gets in.

Each one makes you guess before you read, puts a question between every section, and keeps the model answer locked until you have written your own. That is deliberate — those are the parts that do the work. How to Learn has the evidence.