Maybe you don't understand that the postgraduate entrance examination can't be described as difficult, it depends on which one is more suitable for you. In fact, the difficulty of the postgraduate entrance examination in 985 colleges is similar. As long as you pay, you can enter the basic newspaper.
1 The scientific research strength of the Chinese Academy of Sciences is famous, mainly because they have a group of old professors doing it, rich and various instruments, which are useful but useless.
Tsinghua Peking University, the best university in China, is very strong.
So I said, it depends on which era you are from. Maybe Guangzhou Institute of Biology is doing a good job in virus, leading in China, and you like this major very much, so go to Guangzhou Institute of Biology. The brand of the school is important, but it is still suitable for you.
As for the postgraduate entrance examination, it is still early for you to be a freshman. Learn basic courses well, and start taking professional courses in junior or senior year.
That's it. I hope I can help you. Share it.