The mother of a hospitalized 3-year-old girl expresses concern because her daughter is wetting the bed. What should the nurse tell her

A. "It’s common for a child to exhibit regressive behavior when anxious or stressed. "
B. "Your child is probably angry about being hospitalized. This is her way of acting out. "
C. "Don’t worry. It’s common for a 3-year-olcl child to not be fully toilet-trained. "
D. "The nurses probably haven’t been answering the call light soon enough. They will try to respond more quickly. "

如图所示，一个质量为m的物体以某一速度从A点冲上倾角为30°的斜面，其运动的加速度大小为3g/4，这个物体在斜面上升的最大高度为h，则这个过程中，下列判断正确的是

A．重力势能增加了

B．动能减少了

C．机械能减少了

D．物体克服摩擦力的功率随时间在均匀减小