Targeted: Black and white questions are tailored according to students' learning needs and progress, which can better meet the requirements of students' personalized learning. In contrast, the required questions are too general to be adjusted according to the actual situation of each student.

Sorting out knowledge points: In the design process, the questions in black and white will systematically sort out the knowledge points learned, which will help students consolidate their foundation and form a knowledge system. Mandatory questions pay more attention to the number and difficulty of questions, which may not achieve the same effect.