The person in front of me at ＿＿＿checkout was using ＿＿＿card to check out butfound it wasn't working.

A．不填；a

B．the; a

C．a; the

D．the; the

易感者注射乙肝疫苗

A．一级预防
B．二级预防
C．三级预防
D．一级或者二级预防
E．二级或者三级预防