In the school library, you can only enter the special collection library if you show a certificate issued by the department  If you do not participate in the professor's research group, the department will not issue a certificate  Xiao Zhang was recently recruited into Professor Li's group due to his outstanding performance
Xiao Wang withdrew from Professor Chen's group last week due to personal reasons
Failure to obtain a certificate issued by the department means that you did not participate in the professor's research group.