首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
A、Collect ash tree seeds for experiment. B、Preserve the healthy ash tree seeds. C、Set up a new seed bank for research. D、Develop
A、Collect ash tree seeds for experiment. B、Preserve the healthy ash tree seeds. C、Set up a new seed bank for research. D、Develop
admin
2018-06-27
49
问题
A beetle invasion in the United States has killed at least twenty million ash trees. The invasion of the emerald ash borer was first discovered near Detroit, Michigan, in 2002. Experts believe the small green insects arrived in the 1990’s in shipments of goods from China.
[16] The emerald ash borer has destroyed trees in the Midwest and as far East in the United States as Maryland. [17] The insects have also spread as far north as Ontario, Canada.
Ash trees can resist many diseases. But they cannot resist the emerald ash borer. [18-1] It lays eggs on the bark.The young larva drill into and feed on the inner bark. This harms the ability of the tree to transport water and nutrition.
In some places, farmers are using “detection trees”. They have an area where bark has been cut away. The area circles the tree. [18-2] The process weakens the tree. It makes them easier targets for borers, and shows if the insects are nearby.
Efforts to stop the spread of the emerald ash borer include cutting down affected trees. There are worries that the ash tree might disappear unless the invasion is controlled. To prepare for such a possibility, a government laboratory is asking people to send in the seeds from ash trees. [19] It examines and X-rays the seeds to make sure there are no living borer fertilized eggs.Only the best seeds are remained and then sent for storage in a seed bank. There, they are dried and frozen. Should the seeds ever be needed, the hope is that scientists might someday develop an ash tree that could resist the little green attackers.
1.What’s the speaker mainly talking about?
2.How far do the insects spread northward?
3.Why is part of the bark cut away?
4.What is the government laboratory trying to do?
选项
A、Collect ash tree seeds for experiment.
B、Preserve the healthy ash tree seeds.
C、Set up a new seed bank for research.
D、Develop a new breed of ash tree.
答案
B
解析
转载请注明原文地址:https://kaotiyun.com/show/wKT7777K
0
大学英语六级
相关试题推荐
Throughouthistorymanhasobservedsuchnaturalcyclesastherisingandsettingofthesun,theebbandflowoftheoceantide
A、Earthquakesmayhappenanywhereatanytime.B、Thepreciseplaceandtimeofanearthquake.C、Whetherthemajorityofpeoplekn
TrustMe,I’maRobot[A]Withrobotsnowemergingfromtheirindustrialcagesandmovingintohomesandworkplaces,roboticists
Afterdecadesofdecline,theshareofmotherswhostayhomewiththeirchildrenhas【C1】______risenoverthelastseveralyears,
Forthispart,youareallowed30minutestowriteashortessaybasedonthepicturebelow.Youshouldstartyouressaywitha
中国是率先拥有医药文化的几个国家之一。与西医相比,中医的治疗方法完全不同。经过5000年的发展,中医已经对医药学(medicalscience)、理论、诊断方法、处方等方面形成了一个深刻且全面的理解。中医医生可以没有任何辅助设备,只通过一次体检就能够治
A、Shesaidsomethingunusual.B、Shedidnothaveanyaccent.C、Shehadanorthernaccent.D、Shehadasouthernaccent.D本题问的是收音机
A、AwriterfortheAppointmentsBoard.B、AsecretaryfortheAppointmentsBoard.C、Anythingmatchinghisdegree.D、Hehasnoide
WilmaSubrahadnointentionofbecomingapublicspeaker.After【B1】______fromcollegewithdegreesinchemistryandmicrobiolog
Inthissection,youaregoingtoreadapassagewithtenstatementsattachedtoit.Eachstatementcontainsinformationgiveni
随机试题
考生文件夹下存在一个数据库文件“samp2.accdb”,里面已经设计好表对象“tStafF”、“tSalary”和“tTemp”。试按以下要求完成设计:(1)创建一个查询,查找并显示职务为经理的员工的“工号”、“姓名、“年龄”和“性别”四个字段
(2008年4月)所谓平等,是指公民参加录用考试的______的平等,凡具有应试资格的公民均可报考。
A.活动时不需要任何人的帮助B.完成动作时需要他人监护或体力上的帮助C.患者付出的力占完成动作所需全部用力的50%以上D.患者不能付出任何力,完成动作需要完全帮助E.患者付出的力占完成动作所需全部用力的50%以下,完成动作需要最大或完全的帮助F
对头孢呋辛酯的多晶型现象,为防止其晶型转化,压片时宜采用的工艺
加急秘密××局办公室文件×发(13)第023号请求同意增加人员编制的报告编制办:随着改革开放形式的发展,我局事业蒸蒸日上,人手不够问题日益严重,机关每个工作人员每天都处在十分紧张、经常加班加点的状态,身心疲备,严重
阅读下面的文字,完成38~40题。盖天说与浑天说是中国古代天文学上两大主流学派的理论,两派都创造了许多天文仪器,用于观测、记录、研究和演示天象。浑天学派的浑天仪和浑象奇瑰雄浑,在历史上各受推崇,盖天学派的圭表也广为世人所知。其实,盖天派还创制了一
甲公司董事长乙明知公司已无继续经营的可能,虚构了标的额为1000万元的贸易合同,骗取银行贷款300万元,致使银行损失数额巨大。下列选项中,正确的是()(2015年法学基础课单选第4题)
求由下列曲线所围成的闭区域D的面积:(1)D是由直线ax+by=r1,ax+by=r2,cx+dy=s1,cx+dy=s2所围成的平行四边形闭区域,其中r1<r2,s1<s2,ad-bc≠0;(2)D是由曲线xy=4,xy3=4,xy=8,y3=15所
Itdidn’tseemtohave______toherthatonceshewasaddictedtodrugsmoking,shecouldhardlygiveitup.Butitdidhappen.
PassageFourWhatisthepassagemainlyabout?
最新回复
(
0
)