sb's一般是指具体某人的,如：Jim's,可作形容词性或名词性使用,也可表某一住所.
例：This is Jim's pen.=This pen is Jim's.
Let's go to Jim's （home).
Let's go to the doctor's.(让我们去医务室吧）.
one's 一般 是指形容词性物主代词my,our,your,his,her,its,their,后接名词.
例：Jim is doing his homework now.