汽轮发电机组若联轴器中心错位，则引起相邻两轴承的振动相位（）；因联轴器张口，则引起相邻两轴承的振动相位接近（）。
参考答案：相反；相同
若代数式3-x与-x2+3x的值互为相反数，则x的值是______．
4．______in his office work, he had no time to attend to his sick daughter.
A．Kept engaging
B．Kept engaged
C．Keeping engaging
D．Keeping engaged
