关系代词which, who的选择

Then Needham began his lifelong research，______ ended up creating thegreatest work—Science and Civilisation in China

为何不可以填写who呢，先行词是人Needham，Needham开始他毕生的研究，Needham最后创造了巨著——中国科技史。

Then Needham began his lifelong research，______ ended up creating the greatest work—Science and Civilisation in China.

ended up creating the greatest work 的主语，可以是人，也可以是物，你的想法不是没道理。问题是，定语从句的先行词应该是离它近期的那个词（除去后面的修饰语），不可以瞒山过海隔着谓语动词，去修饰或补充说明句首的那个名词。