Yesterday, I went to the Xinhua Book City and ________ some books about English writing.   [ ]

A. to buy            

B. brought            

C. bought           

 D. buys

以催化反应或能量传递参与发光反应的标记物是（）

A.吖啶酯

B.碱性磷酸酶

C.三联吡啶钌

D.邻苯二胺

E.磷酸酯