please do sth 是请某人做某事的意思,
please not do sth 是请某人不要做某事,是please do sth 的否定形式,
如：oppen the door,用请求的语气please oppen the door显得有礼貌
please not smoke here 请不要在这里吸烟 在交际用语中是固定的用法
Would you please do和前者相同,否定是Would you please not do sth ,有don't you do sth.但不是交际用语,是反问句.don't you go?你不走吗?
交际用语一般用why not do sth.或 why don't you go shopping with me 这样的句子