请教...助动词的补出问题

婉如

224. Inuits of the Bering Sea were in isolation from contact with Europeans longer than Aleuts or Inuits of the North Pacific and northern Alaska.

 

    (A) in isolation from contact with Europeans longer than

    (B) isolated from contact with Europeans longer than

    (C) in isolation from contact with Europeans longer than were

    (D) isolated from contact with Europeans longer than were

    (E) in isolation and without contacts with Europeans longer than

 

    in isolation from

(B)   isolated

(D)     were  

助动词在考试中尽量补出原则

答案；D

1) 补得对不对

2) 和没补的有没有什么其它区别

那 为什么D的 were要 倒装呢？

谢谢

gifile

were可以倒装，没有关系，补出是为了消除歧义。