I memorized the concepts of HTTP in the textbook as if I was studying for a test, but I think I was vague about where and how they were applied. I was able to understand them more deeply by listening to the lecture again. I think this is why I keep listening to Kim Young-han's lectures even though I learned them once. I think it's a great lecture where you can feel that he pays great attention to the details. I especially recommend it to those who have done a web project at least once, even if they are just a little sloppy. It's fun to listen and understand that it was like that at the time. I'll listen to the lecture well and go!