It was only when I reread his poem recently ________ I began to appreciate their beauty.

A．until

B．then

C．that

D．so

女，22岁，尿频、尿急2年，有米汤样尿和终末血尿。尿检；脓细胞（+++），红细胞（+）。尿细菌培养阴性。IVU：左肾未显影，左肾区可见斑片状高密度阴影，右肾盂肾盏显示光滑，有轻度积水。诊断应为（）

A.左肾结核

B.左输尿管结石肾积水

C.双肾结核

D.右肾结核

E.左肾癌