— Did you watch the football match last night?

— Yes, that's a most close one, and eventually neither could defeat _____. [ ]

A. both

B. the other

C. another

D. each

放射免疫分析的必备条件是（）。

A.放射性核素标记的抗原

B.标准品

C.特异性抗体

D.B和F的分离技术

E.抗原标记方法应较温和