It was good that the basic contents were divided into easy-to-understand time units, so I could look at them during my subway commute. However, considering that people without any basic knowledge might have difficulty with in-depth explanations, they only provide explanations for practical use, neither more nor less. Personally, I think we should keep in mind that this is a basic course. Anyway.. I also bought the practical version. I might be able to upload it to the clicker game market soon! Thank you:)