问题描述：
I regret _____ hard at school,or I would have succeeded in passing the exam.
选项:a、not to work b、having not worked c、to have not worked
d、 not having worked
选哪个?为什么?请分析并翻译整句
选项:a、not to work b、having not worked c、to have not worked
d、 not having worked
选哪个?为什么?请分析并翻译整句
问题解答：
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