These placement classes are set for different periods of postgraduate entrance examination. I don't think the whole process is necessary. It's a complete waste of money. Mathematics can be strengthened and highlighted. In fact, it doesn't matter if you don't report politics, because there will be a lot of information on various topics before the exam. If you really don't feel at ease, sign up a few people to attend special classes in different institutions. If you speak English, you should mainly rely on your own efforts. Frankly speaking, remedial classes can't teach anything except some skills, but in the end they have to rely on solid English skills to solve problems, so their own efforts are the most important.

I wonder if my answer can help you.