抗体与抗原结合的部位是()。
A.VL和VH区
B.CH1区
C.CH3区
D.CD4区
E.绞链区
参考答案:A
The student was ________ a gold cup for his excellent performance in the competition.
A.awarded
B.admitted
C.applied
D.advanced
北大校办企业上缴利税比回报学校多多少元( )
A.20亿
B.16亿
C.4亿
D.15亿