【单选题】The Asian countries will remain so mired in the old ways of doing business that reform. will ___.
【判断题】当齿轮的圆周速度v>12m/s时,齿轮润滑采用侵油润滑液。
【单选题】More and more Chinese people want to make connections with the whole world since the Reform. and Opening up. The underlined part means______.
【判断题】当齿轮的圆周速度v ≤12 m/s 时多采用溅油润滑。( )
【单选题】重力为 P ,半径为 R 的均质圆轮受力 F 作用,静止于水平面上,若静滑动摩擦因数为 f s ,动滑动摩擦因数为 f ,滚动摩阻系数为 d ,则圆轮受到的摩擦力和滚动摩阻力偶矩为
A.
F s = f s P ; M f = d P ;
【单选题】当齿轮的圆周速度V>12m/s 时,闭式齿轮传动可采用()润滑方式。
【单选题】对于“金属铝的两性”,理解正确的是?
C.
既能和酸反应(金属性),又能和碱反应(非金属性)
【单选题】重 P 半径为 R 的均质圆轮受力 F 作用,静止于水平地面上,若静滑动摩擦因数为 f s ,动滑动摩擦因数为 f 。滚动摩阻系数为 d ,则圆轮受到的摩擦力 F f 和滚阻力偶 M f 为____________。
A.
F f = f s P , M f = d P
【单选题】Many_____prefer to use the word “ Ms. ” I nstead of “ Miss ” or “ Mrs. ” before their names in business correspondence.
【简答题】Yesterday in oral class, we were talking _________ economic refor,. Somehow we got _______ the subject of inflation.