练习：
1. What is meant by “death chemical” mentioned in paragraph 3？
A A chemical that contains poison. B A chemical that causes death.
C A chemical that announces death. D A chemical that prevents death.
2. Which of the following is closest in meaning to the question “What keeps ants from hauling away the living dead？ （paragraph 4）”？
A How do ants know what is to be hauled away from the dead ants？
B What prevents ants from removing the ants that are not yet dead？
C What do ants do to keep themselves away from the dying ants？
D What prevents ants from being carried away after they die.
3. What is NOT true about Choes finding？
A When an ant dies， it produces a “I am dead” signal.
B Living ants have the death chemical on their bodies.
C Ants have two sets of chemicals on theft bodies.
D Ants have the “I am not dead” chemical on their bodies.
4. According to Choes hypothesis，
A an ant still smells like a living when it dies.
B the “I am dead” chemical leaves the ants body when it dies.
C the “I am not dead yet” chemical is left when an ant dies.
D the “I am not dead yet” chemical leaves the ants body when it dies.
5. What is the result of the test on Choes hypothesis？
A It proves that his hypothesis is time.
B Not enough evidence has been found to support his hypothesis.
C It shows that his hypothesis is wrong.
D It indicates that his hypothesis needs revising.
答案与题解：
1. C 根据文章第二段和第三段的表述，阿根廷蚂蚁身上有种化学物质，它会告诉其他蚂 蚁“I am dead.”。文章没有说这种物质有毒，也没有说它能导致或预防死亡，所以其 他三项都是错误的选择。
2. B keep sb. from doing sth. 这个句型的意思是：使……不做……，阻止……去
做……。所以只有 B 是正确理解。
3. A 第三段和第四段告诉我们，蚂蚁身上会带有两种化学气味，“I am not dead yet” 和“I am dead”。这层意思分别在 B、C 和 D 中的表述出现。短文的第六段告诉我们， 蚂蚁死去时 ，“I am not dead yet”的气味就离开了它的躯体，剩下的就是“I am dead” 的 气味 .“I am dead”的气味不是死后新产生的化学物质。所以 A 是正确的选择。
4. D 短文第六段告诉我们，当“I am not dead yet”化学物质离开蚂蚁的躯体，“Im dead” is left.这里，be left 的意思是：留了下来。所以，其他选项都是错误理解。
5. A 最后一段告诉我们，Choe 和他的研究小组用阿根廷蚂蚁蛹进行实验，结果与他的假 设吻合，即证实了他的假设。