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				 The research is so  designed that once         nothing can be done to change it.A. begins                             B.  having begunC. beginning                          D.  begun[解析] D.由于 the research 與 begin 是被動關(guān)系.故用過去分詞 begun.Once begun 可視為 once it is begun 之省略.			【查看更多】
			


		
           
          


		
          
		
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           The research is so designed that once _______ nothing can be done to change it.
            
          A. begins B. having begun
            
          C. beginning   D. begun
          

			
          
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           The research is so designed that once ____ nothing can be done to change it.  
            
           A. begins B. having begun C. beginning D. begun 
          

			
          
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           The research is so designed that once _______ nothing can be done to change it.
            
          A. begins  B. having begun  C. beginning  D. begun
          

			
          
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          The research is so designed that once _______ nothing can be done to change it. 
            
          A. begins            B. having begun     C. beginning     D. begun
          

			
          
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           The research is so designed that once _______ nothing can be done to change it.
            
          A. begins B. having begun
            
          C. beginning   D. begun
          

			
          
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