I think since you have done the basic questions carefully, you are still wrong, which shows that your mastery is not firm enough. Some basic questions seem simple, but in fact they are easy to make mistakes. For example, when filling in the blanks and choosing right or wrong questions, the questioner is always looking for those points that are easy to make mistakes, and a slight deviation in understanding will easily be "pitted". Therefore, if you want to do the basic questions well, you still have to understand them thoroughly and lay a good foundation.

The so-called problem is not necessarily difficult, but it is beyond the scope of textbooks in knowledge. As long as we find a breakthrough, we can do it right. Of course, you can solve difficult problems, which shows that you are smart! Come on! You can do it!