通过学校international office收到了回复，好像每个人都要security check
Your request for expedited processing is denied. Although this case is
outside of our normal processing times, the processing of the case has been
delayed. A check of our records establishes that this case is not yet ready
for decision, as the required security checks remain pending.
Until the security checks have been completed, we cannot move forward on
this case. These security checks are required to be completed on all
applicants who apply for this type of immigration benefit. We will make
every effort to make a decision on this case as soon as the security checks
are complete. If the applicant does not receive a decision or other notice
of action from us within two weeks of this letter, please instruct him to
contact the National Customer Service Center
