If you don' t know the word, please ______ in the dictionary. [ ]

A. look up it

B. look it up

C. look them up

D. look up

与荧光免疫技术相比，ELISA主要应用于

A．测定分化抗原

B．测定受体

C．测定微量物质

D．鉴定细胞

E．鉴定病原体