烧伤的严重程度分类主要根据是
A．病人年龄
B．致伤因子
C．烧伤部位
D．烧伤面积和深度
E．病人体质
参考答案：D
It's not his work that bothers me. It's his attitude ____ his work.[ ]
A. on
B. towards
C. of
D. over
电压继电器也分为欠电压继电器和（）继电器。
A.过电压
B.过电流
C.欠电流
