"Don't they always exchange sophomores? Surely it has nothing to do with us."
Sophomores are unlike freshmen. Sophomores have already taken some of the core classes, and they have a certain level of understanding of the subjects, although they still have a lot to learn.
And they are unlike juniors. Juniors are about to graduate, and most are already planning for work or for graduate school.
The difference between sophomores and seniors are even more obvious.
Exchanging sophomores is the most productive thing to do, because a lot of discussion takes place, and the discussion helps in securing the fundamentals.
Of course, the exchange program is also meant as a sort of competition.
Tsinghua University and Beijing University have been longtime competitors in all fields. Their rivalry has never ceased.
