题目

In the 1960s, Douglas McGregor, one of the key thinkers in the art of management, developed the mow famous Theory X and Theory Y. Theory X is the idea that people instinctively   51   work and will do anything to avoid it. Theory Y is the view that everyone has the potential to find satisfaction in work. In any case, despite so much evidence to the   52  , many managers still agree to Theory X. They believe,   53   , that their employees need constant supervision if they are to work effectively, or that decisions must be imposed from   54   without consultation. This, 辛烷C8H18在一定条件下受热裂化，生成CH4、C2H6、C2H4、C3H6、C4H8五者的混合气体，此混合气体的平均相对分子质量可能为（　　） A、14B、38C、57D、无定值