词汇	cleaning ball
释义	cleaning ball 建清洗球
随便看	system of open space system of operation system of operation and management system of operation signature system of operator equations system of optional courses system of ordinary differential equations system of ore dressing system of organism signal system of organization system of organization and operation system of organizations and mechanisms system of orthogonal functions system of orthogonal polynomials system of orthograph system of orthonormal functions system of oscillators system of overall financial responsibility system of ownership system of ownership of the means of production system of ownership structure system of parabolic equations system of parallel forces system of parameters system of parental rights