211.
(GWD-8-Q39)
Whereas in mammals the tiny tubes that convey nutrients to bone cells
are arrayed in parallel lines, in birds the tubes form a random pattern.
A.Whereas in mammals the tiny tubes that convey nutrients to bone cells are
arrayed in parallel lines, in birds the tubes
B.Whereas the tiny tubes for the conveying of nutrients to bone cells are arrayed
in mammals in parallel lines, birds have tubes that
C.Unlike mammals, where the tiny tubes for conveying nutrients to bone cells are
arrayed in parallel lines, birds’ tubes
D.Unlike mammals, in whom the tiny tubes that convey nutrients to bone cells are
arrayed in parallel lines, the tubes in birds
E.Unlike the tiny tubes that convey nutrients to bone cells, which in mammals are
arrayed in parallel lines, in birds the tubes
答案A 请教，D错在哪里，whereas在使用上有什么规则，和whether优先取舍之说吗？谢谢 | 
