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.
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, is (E) in that they are composed of tissues such as tooth and bone, tissues the answer is e in that和because的区别? 为什么一定要用同位语呢?是因为容易产生歧异,把they are composed of tissues 和tooth and bone not normally found看成并列么?