According to the passage, what did small children do when they were asked to count a pile of red and blue pencils a. They counted the number of pencils of each color. b. They guessed at the total number of pencils. c. They counted only the pencils of their favorite color. d. They subtracted the number of red pencils from the number of blue pencils.

尿酸测定（）。

A．二乙酰-肟法

B．双缩脲法

C．Jaffe法

D．紫外分光光度法(290nm)

E．ELISA

下列物质测定的方法是