HP1010打印时候进多页纸，应更换（）
A.搓纸轮
B.分页器
C.硒鼓
D.机械故障
参考答案：B
请你写出一个有一根为1的一元二次方程：______；方程x2-5x=0的解是______．
Current data suggest that although ______ states between fear and aggression exist, fear and aggression are as distinct physiologically as they are psychologically.
A. simultaneous B. serious C. partial D. transitional
