男，15岁，因右侧腰部酸胀，劳累后加重就诊，无发热和肾绞痛史。B超右肾中度积水。尿常规正常。

进一步应先做（）

A.IVU

B.KUB

C.CT

D.逆行性输尿管造影

E.放射性核素扫描

—Such a mistake could have been avoided.

—Unfortunately, he ________ the mistake again and again.

A．repeated

B．would repeat

C．had repeated

D．would have repeated