单项选择题
A.do not work, never meetB.have not worked, never have metC.hadn't worked, would never have metD.shouldn't have worked, I should have never met
A.The first widely published development in modem motivation theory.B.Shifting the focus of human motivation from economics to a multifaceted approach.C.The importance of careful research.D.The results of a pioneering study at Western Electric.
A.The nature of radar.B.Types of ranging.C.Alternatives to radars.D.History of radar.