定语从句、补语从句及同位语从句的区别是什么（本质区分方法，我总混淆）？请举例说明。另外ArecentcaseconcernsJaneButlinwhosefiancé,John,runsasuccessfulfurniturebusiness中whosefiancé,John,runs

　　定语从句、补语从句及同位语从句的区别是什么（本质区分方法，我总混淆）？请举例说明。另外ArecentcaseconcernsJaneButlinwhosefiancé,John,runsasuccessfulfurniturebusiness中whosefiancé,John,runsasuccessfulfurniturebusiness是什么从句？