269 During the Remaossance, scholars were uncertain as to the location of Troy, and by the eighteenth century many historians doubted that Troy had ever existed.
A) doubted that Troy had ever existed （A ）
B) doubt that Troy has ever existed
C) were in doubts as to the existene of Troy
D) were doubtful concerning Troy's existence
E) had doubts about Troy's ever existing
不明白为什么E不对。have sb's doubt about sth (见LONGMAN） 时态上由BY引导用过去完成时态也可以啊。 | 
