Could you please 是can you please 更為禮貌、委婉的說法,並不是過去式,是“能否麻煩你……”、“請你……”的意思,更側重“能否”及客觀情況;回答時要注意,eg:A:“Could you please open the window?”肯定回答 B:“Of course”;否定回答:B:“Sorry,I can't open it because the windows are locked on the train.”
而Would you please 含有說話者一定的希望,期待對方願意做某事的意味,“請你……”,更側重“願否”及主觀能動;回答時要注意,eg:A:“Would you please open the window?”肯定回答:B:“OK”;否定回答:“I'm sorry,but don't you feel it is a little bit too cold outside?”
盡管兩者有小小差異,但是在日常口語中,似乎兩者經常通用,並沒有區分得那么明顯.
https://www.zybang.com/question/494332f29a80adc175e3898d4529317b.html