1, first of all, the black paper highlights the required test points, and the answering activity column re-explains; The white paper focuses on supplementary speculation.

2. Secondly, black paper forces a guess and explanation. After checking and analyzing the black paper (there are expanded guesses and activity columns in the analysis), you can practice all kinds of required test sites and questions, using black paper first.

3. Finally, it can be consolidated with white paper.