Multiple choice questions generally adopt exclusion method or special value method, of course, some multiple choice questions can only be done by solving problems.

For big questions, you can only see whether you have learned a solid lesson: generally speaking, in ordinary mathematics learning, you must master a problem every time you do one. This is not remembering the process, but really understanding and mastering. Personal experience holds that only the questions you have done can be told to others or yourself, which is called true mastery. Try to do it. Don't worry that you will do fewer questions than others. Believe me, if you do it well for a while, you will feel that you have more and more solid things than before.