单项选择题 P键用于（ ）。 A、起动变频器 B、停止变频器 C、访问参数 D、减少数值

单项选择题 白血病护理最重要措施是预防和观察 （） A 口腔溃疡 B 脑出血 C 药物不良反应 D 尿道出血 E 贫血性心力衰竭

多项选择题 下面功能中可以调整图像的亮度的是(      )。

判断题 大众汽车公司是欧洲最大的汽车公司,创建于1938年,费迪南德·保时捷是主要创建人.正确错误

单项选择题 Consider an object on a rotating disk a distance r from its center, held in place on the disk by static friction. Which of the following statements is not true concerning this object? A、If the angular speed is constant, the object must have constant tangential speed. B、If the angular speed is constant, the object is not accelerated. C、The object has a tangential acceleration only if the disk has an angular acceleration. D、 If the disk has an angular acceleration, the object has both a centripetal acceleration and a tangential acceleration.