Question

whose和of which 引导定语从句时的区别。

先说明区别，再各造一个句，还有of which引导时它修饰的单词的位置。

Answer 1

whose引导定语从句时，只能在句中作定语。which引导定语从句可以在句中主语和宾语，有时也作定语。of which引导定语从句，在句中作定语。
Do you know the one whose car is BMW?
Do you konw the book which I borrowed from the library?

Answer 2

meaning作为意思是可数名字，B没有加s。懂吗，不懂还可以再问。