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.
But theres a twist to Choes 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, its telling other ants that its dead5.
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.
To test his hypothesis, Choe and his team put different chemicals on Argentine ant pupae. When the scientists used the m dead chemical, other ants quickly hauled the treated pupae7 away. When the scientists used the Wait- Im 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.
Zombie n 还魂尸，僵尸 Pupa n.蛹
hypothesis n.假设
注释：
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、洛杉矶分校、 圣地亚哥分校、圣克鲁兹分校等。
But theres a twist to Choes 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。
turned up：发现，找到。
练习：
A A chemical that contains poison. B A chemical that causes death.
Which of the following is closest in meaning to the question What keeps ants from hauling away the living dead? ?
B What prevents ants from removing the ants that are not yet dead?
D What prevents ants from being carried away after they die.
A When an ant dies, it produces a I am dead signal.
C Ants have two sets of chemicals on theft bodies.
According to Choes hypothesis,mda.com
B the I am dead chemical leaves the ants body when it dies.
D the I am not dead yet chemical leaves the ants body when it dies.
A It proves that his hypothesis is time.
C It shows that his hypothesis is wrong.
答案与题解：
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。
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。