题目

一物体沿固定的粗糙斜面匀速下滑，物体在下滑过程中 A . 动能不变，势能减小，机械能不变 B . 动能不变，势能减小，机械能减小 C . 动能增大，势能减小，机械能不变 D . 动能增大，势能减小，机械能减小 答案：B －Do you know what EU stands for, Tommy? －Sure．It stands for the European Union, _________ European political and economic organization that encourages trade and friendship between _________ countries that are members． [　　] A． an; the B． a; the C． the;/ D． an;/