----My car broke down yesterday on the way to the Yue Lu mountain.

----I am sorry to hear that, but you _______that car every day for ten years before it broke down. Now you really need to buy a new one.

A. have used      B. have been used    C. had used     D had been used

癌症是多基因、多步骤发展的疾病，但不包括（）。

A.癌基因的激活、过度表达

B.抑癌基因的突变、丢失

C.微卫星不稳定，出现核苷酸异常的串连重复

D.错配修复基因，导致细胞遗传不稳定或致肿瘤易感性

E.遗传因素在癌症的发生中起着决定性作用