主要Ig的特性和功能中,“可作为B细胞分化成熟标记”属于()
A.IgG
B.IgM
C.IgA
D.IgD
E.IgE
参考答案:D
A () infected computer may lose its data.
A.file
B.data base
C.virus
D.program
— How about your journey to Mount Emei — Everything was wonderful except that our car ______ twice on the way.
A. slowed down B. broke downC. got down D. put down