the river whose banks are covered with trees is very long,这个句子咋改写

题目

the river whose banks are covered with trees is very long,这个句子咋改写
当先行词指物时 whose可用of whivh the 名词或者 the 名词 of which 来替换
两种改法都告诉我 ,顺便说下原因,

答案

the river of which
banks is covered with trees is
very long.
the river,the
banks of which is covered with trees ,is
very long.
第一个是定从,第二个是同位语