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?
分成兩句話就是
Do you know the difficulty?
He had difficulty (in) finishing the work.
所以,這里的定語(yǔ)從句是he had finishing the work.
如果是為了完成工作,你知道他有的困難嗎?
這個(gè)意思就不對(duì)了.為了完成工作，你知道他有的困難嗎？我覺(jué)得意思挺對(duì)的呀~你知道他有的困難（的目的）是為了完成工作？什么邏輯？為了完成工作，你知道他有的困難不就也可以理解為你知道他為了完成工作有的困難嗎？to finish the work做狀語(yǔ)時(shí)，邏輯主語(yǔ)是句子主語(yǔ)。也就相當(dāng)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的邏輯主語(yǔ)是he，不是you