_______ the website of the Five Department in your city, and you will learn a lot about firefighting.

A．Having searched

B．To search

C．Searching

D．Search

电化学发光免疫测定的底物是（）

A.四甲基联苯胺

B.三丙胺

C.三联吡啶钌

D.异硫氰酸荧光素

E.吖啶酯