_____ in thought, he didn't notice his teacher coming into the classroom at all. [ ]

A. Losing    

B. Having lost  

C. Lost          

D. To lose

患者，有隐匿性肾炎病史3年，间断发作肉眼血尿，持续镜下血尿，伴有头晕耳鸣，五心烦热，腰膝痠软，舌红，苔薄黄，脉细数。方剂宜选用

A．茜根散

B．导赤散

C．小蓟饮子

D．清心莲子饮

E．知柏地黄丸