It's very simple. It's the same as the truth that food is delicious. Seeing is believing. My friend learned it in it. I accompanied him when he signed up. We learned it after tasting it. It's practical. My friend wrote a lot of notes, and made a video to save it. The teacher will guide him on the spot. It's all very detailed. After reading the anonymous user's answer, I can clearly tell you that my peers maliciously slandered.