According to the passage, the worst destruction by locusts in the plains area east of the Rockies occurred during the______. A.eighteenth century B.early nineteenth century C.late nineteenth century D.twentieth century
A.A.eighteenth B.early C.late D.twentieth
【参考答案】
C 解析：文中第二句说：“这些昆虫的大规模的成群迁徙曾经使落基山脉的东部平原暗无天日，那里的庄稼通常被破坏掉；最......