2. The investigation of the three-level function of the senior high school entrance examination is nothing more than choosing or filling in the blanks in the questions and solving the right angles. Be sure to write it in the right angle.

3. yes. In fact, reviewers can also understand your answers.

4. This won't work. There is no relevant theorem in the book, so you need to prove it yourself.

5, some knowledge of high school, no.