Verrazano,(主语)an Italian (同位语)with whom little is known about (定语从句) be known about 为固定词组 还原从句:little is known about whom,whom就指代这个意大利人
whom在从句中做介词about的宾语.楼主问whom可以用who来代替么?正式的用法是不可以的,关系代词whom是who的宾格形式,在从句中做宾语成分,此处缺的就是介词的宾语,who在从句中做主语成分.
在定语从句中,如果引导词whom,which在从句中作宾语时,引导词通常省略.若遇到从句中是“不及物动词+介词+宾语”的情况时,介词可提前到引导词前,也就是“介词+whom/which”结构.
如下例:
the girl whom your mother is talking with is my girlfriend可写为 the girl with whom your mother is talking is my girlfriend 和你妈妈谈话的女孩是我的女朋友
ps:关于楼主写的这句Verrazano,an Italian (which) who little is known about,sailed into New York Harbour in 1524 and named it Angouleme是不对的,为什么呐?因为an Italian 是表示人,先行词是人的时候,引导词应该用who或that.which是修饰限定表示事物的名次或代词,不能用在这里.而且从句缺的是宾语,只能用whom