成年人最少见的继发性肾病综合征的病因是（）

A.过敏性紫癜肾炎

B.遗传性肾病

C.系统性红斑狼疮肾炎

D.淀粉样变肾病

E.骨髓瘤性肾病

Ten years ____,he studied at school, Now he is a successful doctor.

A．later

B．ago

C．behind

D．after