To be honest, the quality of the lectures is not that good. When I went to take the actual exam, I cursed inside because almost 1/3 of the content was not in the lectures. I chose Core because I thought it would be easier than Expert because I needed a certificate urgently, but there are not many mock exams for the Core version that have been released, so I paid for the lectures, but the quality is low, so I don't feel good. In particular, I didn't like that they didn't give me a separate exam paper for the mock exam part, so I had to look at each question and do them. I also thought that the fact that mock exams 2, 3, and 4 were too short compared to the actual exam was not done properly.