阅读下面的短文。每篇短文的后面有五个问题，每个问题有四个备选答案。请根据短文的内容选择最佳答案。每个试题计3分,共计15分
　　Where Have Allthe Bees Gone?
　　Scientists who study insects have a real mystery on theirhands．All across the country，honeybees are leaving their hives and neverreturning． Researchers call this phenomenon colony-collapse1 disorder．Accordingto surveys of beekeepers across the country，25 to 40 percent of the honeybeesin the United States have vanished from their hives since last fall．So far，noone can explain why．
　　Colony collapse is a serious concern because bees playan important role in the production of about one-third of the foods we eat．Asthey feed，honeybees spread pollen from flower to flower．Without this process，aplant can’t produce seedsor fruits．
　　Now，a group of scientists andbeekeepers have teamed up to try to figure out what’s causing the alarmingcollapse of so many colonies． By sharing their expertise in honeybee behavior，health，and nutrition，team members hope to find out what’s contributingto thedecline and to prevent bee disappearance in the future．
　　Itcould be that disease is causing the disappearance of the bees． To explore that possibility，Jay Evans，a researcher at the United States Department ofAgriculture (USDA) Bee Research Laboratory2，examines bees taken from coloniesthat are collapsing．“We know what a healthy bee should look like on theinside，and we can look for physical signs of disease,” he says． And bees fromcollapsing colonies don’t look very healthy． “Their stomachs are worndown，compared to the stomachs of healthy bees,” Evans says．It may be that aparasite is damaging the bees digestive organs． Their immune systems may not be working as they should．Moreover，they have high levels of bacteria inside theirbodies．
　　Another cause of colony-collapse disorder may be certain chemicalsthat farmers apply to kill unwanted insects on crops，says Jerry Hayes，chief beeinspector for the Florida Department of Agriculture3．Some studies，hesays，suggest that a certain type of insecticide affects the honeybee’s nervoussystem (which includes the brain) and memory．”It seems tike honeybees are goingout and getting confused about where to go and what to do,” he says．
　　If itturns out that a disease is contributing to colony collapse，bees genes couldexplain why some colonies have collapsed and others have not．In any group ofbees there are many different kinds of genes．The more different genes a grouphas，the higher the group’s genetic diversity．So far scientists haven’tdetermined the role of genetic diversity in colony collapse，but it’s a promisingtheory，says Evans．
　　词汇：
　　honeybee/5hQnIbi:/n．蜜蜂 parasite/5pArEsait/n．寄生虫；寄生生物
　　hive/haiv/n．蜂巢；蜂箱 digestive/di5dVestiv,dai-/adj．消化的
　　pollen/5pClEn/n．花粉 immune/i5mju:n/adj．免疫的
　　beekeeper/5bi:ki:pE (r)/n．养蜂人 insecticide/in5sektisaid/n．杀虫剂
　　expertise/7ekspE5ti:z/n． diversity/dai5vE:siti/n．多样性
　　专门知识，专长注释：
　　1． colony-collapse：群体瘫痪。colony有“殖民地”的意思，在此意为：a groupof the same kind of animals，plants，or one-celled organisms living or growingtogether．一群生活或生长在一起的同种动物、植物或单细胞有机体。
　　2． the United States Department ofAgriculture(USDA) Bee Research Laboratory：美国农业部蜜蜂研究实验室。
　　3． the FloridaDepartment of Agriculture：佛罗里达农业局。佛罗里达是美国东南部的一个州，濒临大西洋和墨西哥湾。

　　练习：
　　1． What is the mystery that researchers find hard to explain?
　　A Honeybeesare flying all across the country．
　　B 25-40 percent of the honeybees inthe US have died．
　　C Honeybees are leaving their hives and do not return．
　　D Honeybee hives are in disorder．
　　2． Why are researchersseriously concerned with the phenomenon of colony-collapsedisorder?
　　A Because honeybees produce one-third of the foods we eat．
　　B Becausehoneybees feed on flowers．
　　C Because honeybees eat seeds of flowers．
　　D Both B and C．
　　3． What are the possible causes of colony-collapsedisorder given by the scientists?
　　A Worsening environment．
　　B Diseaseand chemicals．
　　C Dwindlingnumber of flowers around．
　　D Changes ingenes’ structures．
　　4． According to the fifth paragraph，which of thefollowing about bees’ genes istrue?
　　A Bees’ genes allow them toexpand their colonies．
　　B Bees’genes help keep them in their hives．
　　C Bees’genes make them fly from flower to flower．
　　D Bees’genes couldexplain the collapse of some colonies．
　　5． What explanation is given byJerry Hayes to the phenomenon?
　　A Farmers apply certain chemicals to killunwanted bees．
　　B The insecticide destroys the honeybee’s nervous system．
　　C The insecticide affects the honeybee’s memory．
　　D All of theabove．
　　答案与题解：
　　1． C 短文第一段的第一句和最后一句告诉我们，昆虫学家正面临一个不可解释的谜。第二句解释了这个谜，给出了答案。
　　2． A 短文第二段的第一句提供了答案。蜜蜂传播花粉能使植物结果，因此为人类提供食物。
　　3． B 第四段的开头是It could be thatdisease is causing the disappearance of the bees．第五段的开头是Another cause ofcolony-collapse disorder may be certain chemicals that，这是科学家给出的两个可能造成这种现象的原因。
　　4． D 第六段的句子：bees’genes could explain why some colonies have coilapsed andothcrs have not。这是选择D的依据。选项A、B、C的内容文章中都没有出现，所以不是答案。
　　5． D 第五段描述了另一个可能的原因，即农夫使用的杀虫剂可能破坏了蜜蜂的神经系统和记忆。所以D是正确选择。