精选优质文档-倾情为你奉上2000年41. Acute hearing helps most animals sense the approach of thunderstorms long before people_. A. do B. hear C. do them D. hearing it 答案：A 【参考译文】敏锐的听觉使多数动物能远在人之前感觉到雷雨的来临。 【试题分析】本题为语法题，考句子成份的省略与替代。 【详细解答】“Acute hearing helps”是主句和before引导的从句具有相同的主语和谓语，从句中省略了该相同部分，用助动词do代替了与主句重复的信息“sense the approach of thunderstorms”故答案为选项A。42.This is an illness that can result in total blindness _ left untreated. A. after B. if C. since D. unless
