Do you know the difficulty he had finishing the work

Do you know the difficulty he had finishing the work
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Do you know the difficulty which he had finishing the work?
分成两句话就是
Do you know the difficulty?
He had difficulty (in) finishing the work.
所以,这里的定语从句是he had finishing the work.
如果是为了完成工作,你知道他有的困难吗?
这个意思就不对了.为了完成工作，你知道他有的困难吗？我觉得意思挺对的呀~你知道他有的困难（的目的）是为了完成工作？什么逻辑？为了完成工作，你知道他有的困难不就也可以理解为你知道他为了完成工作有的困难吗？to finish the work做状语时，逻辑主语是句子主语。也就相当于In order that you can finish the work, you know the difficulty he hadDo you know the difficulty which he had finishing the work?中的finishing the work的逻辑主语是he，不是you