【单选题】The students were summoned _______ to be interviewed. A. by turns B. in return C. in turn D. in honor
【单选题】I don’t like the black jumper, but the ______is nice.
【单选题】图示一半径为R的圆柱形容器,内盛有密度为ρ的液体,若容器以等角速度ω绕OZ轴旋转,则A点的压强为()
【简答题】针对加工中心的工艺特点,加工中心适宜的加工对象有哪些?
【单选题】A clock must _____ keeps good time. [ ]