第5题: [单项选择]From the time of the Greeks to the Great War, medicine's job was simple: to struggle with ______ diseases and gross disabilities, to ensure live births, and to manage pain. A. immortal B. immune C. lethal D. toxic 参考答案:C 答案解析:lethal致命的；immortal不朽的；immune免疫的；toxic有毒的。
第16题: [单项选择]链表不具有的特点是 ( ) A. 不必事先估计存储空间 B. 可随机访问任一元素 C. 插入删除不需要移动元素 D. 所需空间与线性表长度成正比 参考答案:B 答案解析:[解析] 链表采用的是链式存储结构，它克服了顺序存储结构的缺点：它的接点空间可以动态申请和释放；它的数据元素的逻辑次序靠结点的指针来指示，不需要移动数据元素。但是链式存储结构也有不组之处：①每个结点中
第18题: [单项选择]Questions 18-21 are based on the following passage.What was the black walnut wood used for in World War I A. It was used to make cabinets. B. It was used in making cigarette filter. C. It was used in making gun stocks. D. It was used to make fences. 参考答案:C 答案解析:本题的关键词句为harvested for gun stocks，nutshells，filtering material in gas masks．从上述关键词可知选[C]。
