saw some trees,the leaves of ___were black with disease

问题描述:

saw some trees,the leaves of ___were black with disease
Athat
Bwhich
Cwhose
Dthe trees

B
定语从句,选择正确的关系代词.which相当于前面的trees,关系代词前有介词(of、in等)修饰时用which不用that排除A,of which 相当于whose