The next four big questions are relatively simple. If you do more similar problems, you will be familiar with them, and the speed of solving them will also increase. Be careful when you do it, don't copy the numbers wrong, and don't put the decimal point wrong. These are all things you should pay attention to in your usual training. Usually, we should do the questions as exams and get rid of carelessness.
The last two questions, especially the last one, must be difficult. Try to do the first two questions. The last question can be blank in the exam. Of course, when you do the problem, you can take a good look at the answer analysis and how much you can master.
A series of small questions recommended by Bowen are fill-in-the-blank questions with moderate difficulty and detailed answers. You can do one set every day, or you can do 3-5 sets every week. It is best to train at a fixed time and for a limited time (30 minutes). Just like an exam, you should train your presence and speed of solving problems, stop writing as soon as possible, and analyze the reference answers for unfinished questions to improve your problem-solving skills.