I think we should buy a set, because many questions are from textbooks, so we will be familiar with the exam. Of course, if you master it, it depends on what textbooks are the same as the exam. But as a basic study, it is best to follow the textbook. In addition, the emphasis of vocabulary in various textbooks is also different. Therefore, if you don't look at the designated textbooks, you may not have an advantage in vocabulary.

Read the book carefully several times and do all the exercises. There is basically no problem.

Please also note that some answers in the references are inaccurate. If your answer doesn't agree with that in the book, you should dare to doubt it. Hey hey. Ask the teacher.