Loved this class! I took the series 1-3 with Professor Choi. The class was online because of COVID, and it was very lax. Tests and quizzes are open note, homework is graded based on completion, and overall the workload is pretty easy. The TAs (Minseung for 1-2, Chungmin for 3) were very helpful and really sweet!! I highly recommend them. There are usually 3 different tests: the oral exam (with a partner), written exam (usually about 10-13 sentences), and the chapter test. They were all done online, and for the written/oral exam, you're allowed to submit your drafts to your TA for a revision. Would definitely take again!