Taobao is Asia’s largest retail（零售的） network platform, ______ people can buy and sell many kinds of things．

A．when

B．whose

C．that

D．where

筛检致癌物最广泛和最敏感的致突变试验是（）。

A.微核试验

B.SCE试验

C.显性致死试验

D.Ames试验

E.SCGE试验