摘要：7．The research is so designed that once nothing can be done to change it．［NMET2002］ A．begins B．having begun C．beginning D．begun [简析]答案为D.once begun在句中作条件状语.它是状语从句once it is begun的省略形式.句意为:这项调查研究事先计划的如此完好.以致于一旦开始.什么也无法改变它.
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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
查看习题详情和答案>>The research is so designed that once ____________ nothing can be done to change it．
A．begins B．having begun C．beginning D．begun
查看习题详情和答案>>
The research is so designed that once ________ nothing can be done to change it．
[ ]
A．begins
B．having begun
C．beginning
D．begun