Regarding your question, my answer is (corresponding to your question):
1. Mathematics is a national unified proposition.
2. Politics is a proposition of national unity.
3. English is a national unified proposition.
4. Specialized courses are independent propositions of all enrollment schools. So as far as specific examination questions are concerned, each school is different. But the reference books of the same major are basically the same. And for the voluntary entrance examination, although two schools can be filled in, only the first one is valid. The second choice is useless. And if you transfer (that is, the first choice is not accepted, but you transfer to other schools to participate in admission, but you basically contact yourself. The first voluntary school basically won't help you contact, but sometimes it will provide you with some information when you meet a good teacher), which has nothing to do with the content of the specific exam, but only with your major. As long as you apply for the same major, you can adjust it, which means you can transfer to another school's international trade major. But there is little chance to adjust, especially this popular major.
As far as international trade is concerned, I have never studied this major, so I don't know much about it. But I learned something through other students' channels (I can't believe China's so-called university ranking is just funny). Foreign trade and economic cooperation is the best in Beijing and the best in China. There is a master's degree in international trade in foreign trade and economic cooperation (it is so unkind to have a man on it, so it's natural to say here if you don't investigate, alas ...). In 2004, 984 people applied for the major of international trade in foreign trade and economic cooperation, with a score of 325, which is higher than the national line 15 (in fact, this is not a comparison, because the major courses are different from school to school, and the major courses in foreign trade and economic cooperation are very difficult); In 2005, 993 people applied for 130, with a score of 342, 7 points higher than the national line; In 2006, 972 people applied for 140, with a score of 350, which was higher than the national line 10. From this perspective, the competition is fierce. But as long as you are fully prepared, you can basically get in. After all, it can be seen from the relatively low scores that it is estimated that many applicants put participation and friendship first. Of course, NPC is also very good, followed by Shangcai, Peking University, Fudan University and Nankai University. Postgraduate entrance examination still needs to be admitted to a better school.
6. Included in the answer to the fourth question.
Finally, good luck!