阅读下列短文，从每题所给的A、B、C、D四个选项中选出最佳选项。
A
Mathematics is becoming more and more important in today's society, but more and more people find themselves unable to learn mathematics. Here are some suggestions for learning mathematics:
Preview in advance
Preview in advance can have a general understanding and grasp of what the teacher says in class, grasp the key points when listening to the class, and focus on the key and difficult points that you won't be able to hear. However, mathematics textbooks are more obscure and difficult to understand. If you only rely on self-study, it is often difficult to look down and learn. Therefore, it is important to grasp the classroom and follow the rhythm of the teacher in class.
Listen carefully
The concept of fixed classrooms in some middle schools is weak, so the place and seats of classes are moving, and classes are basically held in relatively large ladder classrooms. The classroom space is relatively large. It is recommended that you sit in front, which can hear the teacher's lecture more clearly, facilitate interaction with the teacher, and also enable you to concentrate on avoiding missing knowledge points due to distraction.
Review in time
A lot of knowledge about mathematics is connected. We need to review and summarize the knowledge we have learned so that we can master it. Of course, some students don't have enough patience to review, but they also have to review what they learned in the previous class every day. Review also has to concentrate, must be of high quality, high efficiency, and do not procrastinate.
Mastery
The knowledge of mathematics is advanced layer by layer. The knowledge of the next chapter is closely connected with that of the previous chapter, which requires students to study steadily, step by step, and master key knowledge. They must not learn in a hurry. In this way, they can not connect knowledge, but also disrupt the pace of learning and increase the difficulty of learning.
21．How many suggestions does this article provide for learning mathematics?
A. 1 B. 2 C. 3 D. 4
22．Which of the following statements is TRUE according to this passage?
A.The places and seats of middle school students are random
B. Preview the knowledge in advance so that you can fully understand what the teacher said in class.
C. We should study mathematics with high efficiency and quality
D. In order to catch up with the teaching progress, we can learn mathematics knowledge in advance.
23．Where did this article most possibly come from?
A. newspaper B. textbook C. Study Article D. magazine
