Generally speaking, they don't need to take the college entrance examination in China. They're not necessarily. Some people come to learn Chinese, while others learn Chinese first and then other majors. Some are personal, and some are funded by the state.

It is normal for people to adapt to life, but it depends on the speed of personal adaptation. Some people have never been able to adapt, while others adapt quickly. This is also related to the original living environment, so Koreans adapt quickly.