-I hear Tom ________ playing games.

-________ no wonder he is easy to feel sleepy in class.[ ]

A．is addicted to; There is  

B．addicts; There is

C．addicts; It is  

D．is addicted to; It is

诊断单纯性肾病综合征必备的条件是( )

A．血沉明显增快
B．不同程度的水肿
C．大量蛋白尿、低白蛋白血症
D．血胆同醇增高
E．血清补体正常