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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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