2010年职称英语考试(理工类)阅读理解辅导(四)
Night1 of the Living Ants
When an ant dies, other ants move the dead insect out of the nest. This behavior is interesting to scientists, who wonder how ants know for sure – and so soon-that another ant is dead.
Dong-Hwan Choe, a scientist at the University of California2 found that Argentine3 ants have a chemical on the outside of their bodies that signals to other ants, "I'm dead - take me away."
But there's a twist to Choe's discovery4. These ants are a little bit like zombies. Choe says that the living ants - not just the dead ones - have this death chemical. In other words, while an ant crawls around, perhaps in a picnic or home, it's telling other ants that it's dead5.
What keeps ants from hauling away the living dead? Choe found that Argentine ants have two additional chemicals on their bodies, and these tell nearby ants something like, "wait -I'm not dead yet. "So Choe's research turned up6 two sets of chemical signals in ants: one says, "I'm dead," the other set says, "I'm not dead yet."
Other scientists have tried to figure out how ants know when another ant is dead. If an ant is knocked unconscious, other ants leave it alone until it wakes up. That means ants know that unmoving ants can still be alive.
Choe suspects that when an Argentine ant dies, the chemical that says "Wait- I'm not dead yet" quickly goes away. Once that chemical is gone, only the one that says "I'm dead" is left." It's because the dead ant no longer smells like a living ant that it gets carded to the graveyard, not because its body releases new unique chemicals after death," said Choe. When other ants detect the "dead" chemical without the "not dead yet" chemical, they haul away the body. This was Choe's hypothesis.
To test his hypothesis, Choe and his team put different chemicals on Argentine ant pupae. When the scientists used the "I'm dead" chemical, other ants quickly hauled the treated pupae7 away. When the scientists used the "Wait- I'm not dead yet" chemicals, other ants left the treated pupae alone. Choe believes this behavior shows that the "not dead yet" chemicals override the "dead" chemical when picked up by adult ants. And that when an ant dies, the "not dead yet" chemicals fade away. Other nearby ants then detect the remaining "dead" chemical and remove the body from the nest.
词汇：
Zombie n 还魂尸，僵尸 Pupa n.蛹
Graveyard n.墓地
hypothesis n.假设
override v.优先于，比……更重要
注释：
1. night：night 是个多义词，其比喻意义是“死亡”，即本篇短文标题中该词的意思。标 题是用了逆喻的修辞手法。
2. the University of California：加利福尼亚大学，位于美国西部的公立高等学校系统 ，目前拥有10所大学，包括加州大学伯克利分校（Berkeley）、洛杉矶分校（ Los Angeles）、 圣地亚哥分校（San Diego）、圣克鲁兹分校（Santa Cruz）等。
3. Argentine：阿根廷，位于南美洲的国家。
4. But there's a twist to Choe's discovery.然而，Choe 又有了新的出乎意料的发现。 Twist 有“出人意料的变化”的意思。
5. 本句 it's telling other ants that it's dead 中两个 it 指代前面爬行中的蚂蚁，也 就是下段第一句中的 the living dead.
6. turned up：发现，找到。
7. treated pupae：经过处理的蛹，即被科学家涂抹上化学药剂的蛹。
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 Choe's 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 Choe's hypothesis,
A an ant still smells like a living when it dies.