题目

When it was difficult for actor Michael Doresey to get anyone to hire him, he decided to ______ a part in a soap opera as a woman. A . try out for B . live up to C . stand up for D . have power over 答案：A如图所示，小宇从公园里的滑梯上滑下，在滑下的过程中，下列说法正确的是（ ）A．人与滑梯接触部位感到好烫，是因为太阳把滑梯晒热了B．自于惯性，当他滑到滑梯底部时难以立即停下来C．人受到的重力与摩擦力是一对平衡力D．人的重力势能变小，但总的机械能不变