下面哪种情况不需要评价肾段动脉的阻力指数（）
A.急性肾小管坏死
B.药物性肾病
C.急性尿路梗阻
D.肾内动静脉瘘
E.移植肾排异
参考答案：C
I often ____________ to school. But I ____________ to school by car yesterday.[ ]
A. walk; go
B. walk; went
C. walked; went
在C语言中，下面标识符不合法的是( )。
A．sum
B．money$
C．month_1_2
D．_counter
