a good result，the professor decided to do the experiment once more．
A. Not getting
B. Getting not
C. Not having got
D. Having not got
网友回答
A. Not getting
B. Getting not
(答案→)C. Not having got
D. Having not got
解析：考查非谓语动词。逻辑主语the professor，与have之间为主动关系，故用现在分词，根据句意用其完成式，否定应放在分词前。句意：没有得到好的结果，教授决定再次做这个实验。