The first suggestion: There are too few practice questions.
The second suggestion: You can only answer 6 questions a day, which is too few. You should let the learner choose how many questions to answer. The experience in this regard is average.
The third suggestion: How to get more customers to use the skill tree, you can make a monthly points list, and you can get prizes with high points.
The fourth suggestion: collect the skill tree and pass the review. Some articles are of different levels, high and low. You can invite excellent bloggers to write a skill tree system, so that learners can test that skill tree article is more acceptable. After screening, a unified author article style is used.
The fifth suggestion: the sign-in client and the pc-side whole station are used synchronously!
