1.It"smy/apleasure.和Mypleasure.是回答别人说“谢谢”时使用,有“不用谢（这是我的荣幸）”的意思.

而Withpleasure.是用于别人问你“能给我给帮助吗?（Couldyouhelpme…）”有“乐意帮你”的意思.

2.另it"apleasure:-Thanksforyourhelp.-It"sapleasure(没有关系)

it"mypleasureA:Thankyouforyouradvice.B:it"mypleasure/It"sapleasure(没有关系)

apleasure-------Itisapleasuretotalkwithyou----和你交谈是种乐趣

mypleasure：-Thanks.-Mypleasure/it"mypleasure/It"sapleasure(没有关系)

withpleasure-----很乐意,很情愿--------Canyoudoitforme?-Withpleasure.

withmypleasure(英语中应该没有这种表达)