问题
选择题
. The book, _______ is blue, is mine.
A．the cover of which
B．whose cover
C．of which the cover
D．all the above
答案
答案：D
考查定语从句，先行词是the book，定语从句缺少cover的定语，用whose cover引导，="of" which the cover也等于the cover of which，所以选D，句意是：封面是蓝色的书是我的。选D。