That a different component part of the vaccine is necessary is principally due to the variable change of ______.

A．Supervising the assessment of influenza virus strains.
B．Holding meetings twice a year to provide the latest data concerning the composition of the vaccines.
C．Publishing the related information in a WHO almanac.
D．Stressing the importance of preventing influenza for people living in tropical areas of Asia.

A．force departments to give graduates more teaching time
B．try to persuade universities to change their ways
C．dictate the standard of thesis required by external examiners
D．note that students want more research training and less elaborate style of thesis