They ______ on the program for almost one week before I joined them, but still no good results _______ so far.

A．had worked ; come out

B．have worked ; came out

C．had been working ; have come out

D．have been working ; have come out

“从世界史的观点来看，美国革命之所以重要并不是因为它创造了一个独立的国家，而是因为它创造了一个新的、不同类型的国家。”对“新的、不同类型”的正确理解是  [ ]

A．确立了现代政党制度

B．实现了民族的独立

C．确立了议会主权原则

D．开创了现代政体新形式