能激活补体经典途经的Ig是()
A. IgG1、IgG2、IgG3、IgM
B. IgG1、IgG2、IgG4、IgM
C. IgIgIgIgM
D. IgG4、IgIgIgD
E. 凝聚的IgG4、IgIgE
IP地址的主要类型有几种:()
A. 4
B. 5
C. 6
D. 7
Although a teenager,Fred could resist__________ what to do and What not to dO.
A. being told
B. telling
C. to be told
D. to tell
It is high time that such practices。.
A. are ended
B. be ended
C. were ended
D. must be ended