208, Teratomas are unusual forms of cancer
because they are composed of tissues such as tooth and bone not normally found in the organ in which the tumor appears.
A. because they are composed of tissues such as tooth and bone
B. because they are composed of tissues like tooth and bone that are
C. because they are composed of tissues, like tooth and bone, tissues
D. in that their composition, tissues such as tooth and bone, tissues
E. in that they are composed of tissues such as tooth and bone, tissues
答案是E,
我觉得a也挺对对的啊。。。。。求教。。。。。
-- by 会员 chinasharon (2011/3/23 13:51:59)