请教一道语法题

xd2008

Until a few centuries ago, any large bones discovered in the fields or caves of Europe, now known to be large prehistoric animals, were usually assumed to be the remains of giants and were often displayed as curiosities in castles, palaces, town halls, churches, and monasteries.

(A)   now known to be large prehistoric animals, were usually assumed to be

(B)   presently known as from large prehistoric animals, were usually assumed as

(C)   boned now known to be those of large prehistoric animals, were usually assumed to be

(D)  bones known at present as of large prehistoric animals, were usually assumed as those of

(E)   currently known as those of large prehistoric animals, were usually assumed to be those of

答案是C，B是什么问题？

serendipityh

known to be
assume as 好像我没见过这用法呢!
字典里没有啊!

lijiahui0422

B里面的presently known ...修饰不清，C通过重复修饰名词bones解决了这个问题