急性肾衰竭持续存在的主要因素是（）。

A.肾血流动力学改变

B.肾小管上皮细胞变性、坏死

C.肾缺血-再灌注损伤

D.感染或药物引起的间质性肾炎

E.非少尿型急性肾功能衰竭

It was during World War II, ____ he was in his early twenties, _____ he joined the British Army.

A．that; when

B．when; that

C．when; when

D．that; that