1. Single mode test is moderately difficult. It will start at the end of the first round of review, and the examination content will cover all the key points of the textbook. Moreover, this is the first time for students to take a large-scale mock exam, and the experience and skills in the exam need to be summarized and improved from these practical exercises.

2. Compared with the first mode and the third mode, the second mode is much more difficult. After all, with the accelerated pace of review and the progressive depth of review, students' mastery of knowledge is also rapidly improving. Therefore, the second mode is more like touching the "ceiling" of students.

3. The three modes are the least difficult, because the college entrance examination is often close at hand, and at this time, there is only one thing that students need most, and that is to stabilize their mentality.