Question

__with the book I bought yesterday,the one borrowed from the libray doesn't seem interesting.

A,When compared BWhile comparing C,comparing
答案是A，
B和C为什么不对？？
我记得有些题开头都是用ING形式的。。。哎。。。迷惑啊
求解，谢谢。。。。

Answer 1

因为这里省略了it is ,
完整句子是When it is compared with the book I bought yesterday,the one borrowed from the libray doesn't seem interesting.===The one borrowed from the libray doesn't seem interesting when it is compared with the book I bought yesterday.
当与我昨天买的那书相比时，我从图书馆借来的那本似乎不怎么吸引人了。

it是代词，指的就是The one borrowed from the libray ，从图书馆借来的那本书
因为句子的主语是The one borrowed from the libray ，而后面也是同样的主语，这时候相同的主语可以 省略，所以就变成了when compared with....

compared这里是 ed形式，有被动的意味，一般主语是物，例如这里的book
而comparing 是ing形式，有主动的意味，一般主语是人，而且直接是comparing sth.

例如While comparing the book I bought yesterday, I found the one borrowed from the libray doesn't seem interesting.=======I found the one borrowed from the libray doesn't seem interesting while comparing the book I bought yesterday, 这里主语就是人。

C 跟B类似，应该是Comparing the book I bought yesterday, I found the one borrowed from the libray doesn't seem interesting