这句话里面的to是不定式符号,引导后置定语——这个教授几乎不能找到充足理由,为他的辩论奠定基础支持他的理论的理由.
which不是从句（没有谓语）,which 指代前面的sufficient grounds ,和base on 句型套用在一起,on提前了which 指代前面的sufficient grounds ，which 是单纯的代词吗，The professor can hardly find sufficient groundsto base his argumenton which in favor of the new theory。这种语序可以吗不可以，这样可以：The professor can hardly find sufficient groundsto base on his argumenton h in favor of the new theory。那Which不就没了嘛，你这个句子不是定语从句，which只起指代作用，和这道题一样it is unusual for a seller to be able to find a unique selling point or a competitive advantage with which to convince the customer .with the advantage of具备...的优势...advantage （with which to convince the customer ）只不过是咱们的这道题：base on把on提前了