It should be that many of their works are suspected of plagiarism. For example, the youth practice manual copied the silent king, don't sleep late (the prelude is easy to hear), the name of faith copied the robe Jie op (even the tone has not changed), and the favorite should be the copied Liang Xu exam. Go to hell (many people have heard this song, and all the students in our class say that their favorite sounds familiar). I usually like Liang Xu, so I can hear it. Although it is not as serious as plagiarism, it is similar.