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、To clear up the eggs of insects. B、To help trees deliver water. C、To look for the signs of insects. D、To prepare for cutting d
A、To clear up the eggs of insects. B、To help trees deliver water. C、To look for the signs of insects. D、To prepare for cutting d
admin
2019-02-18
97
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、To clear up the eggs of insects.
B、To help trees deliver water.
C、To look for the signs of insects.
D、To prepare for cutting down trees.
答案
C
解析
转载请注明原文地址:https://kaotiyun.com/show/wlH7777K
0
大学英语六级
相关试题推荐
ManyworkerswhoworkedintheWorldTradeCenteraftertheSeptembereleventhattacksbecamesick.Theybreathedamixofdust,
ArecentBBCdocumentary,"TheTownThatNeverRetired",soughttoshowtheeffectsofincreasingthestatepensionagebyputti
Ourbodiesexperienceanebbandflowofenergythroughouttheday.Thisiscalledacircadianrhythm,andithasbeenstudied【C
A、HewasoneofthegreatestemperorsinHanDynasty.B、HebroughttoPersiaanewbreedofhorsefromChina.C、Hewasconsidere
A、Cookedmeatproductsaresafetoeat.B、Peopleshouldeatlesspopularpreparedfoods.C、Todecreasesalt,popularpreparedfo
Farmersusuallyuseploughstopreparetheirfieldsforplantingcrops.Ploughscutintotheground,andliftupweeds,andothe
Farmersusuallyuseploughstopreparetheirfieldsforplantingcrops.Ploughscutintotheground,andliftupweeds,andothe
Directions:Forthispart,youareallowed30minutestowriteanessaycommentingontheagingofpopulationinChina.Youcan
随机试题
时间艺术:______、_______。
右心衰竭引起淤血的器官主要是
病案整理过程包括资料的装订,病案装订的方式是
1989年,某国家儿童中发生了艾滋病病毒感染的暴发流行,经调查,可能的原因是
清热利湿而利胆退黄,为治湿热黄疸之要药的中药是
一平面简谐波的波动方程为y=0.1cos(3πt—πx+π)(SI),t=0时的波形曲线如图所示,则下列叙述中哪个正确?
某施工企业2015年度利润表中营业利润为1000万元,营业外收入200万元,营业外支出100万元,适用所得税率25%,则当期所得税为()。
绩效的卓越标准是指企业未做要求和期望,其作用是()。
下列关于投资性房地产转换的会计处理,表述正确的是()。
在学生表中共有100条记录,执行如下命令,执行结果将是INDEXON-总分TOZFSETINDEXTOZFGOTOPDISPLAY
最新回复
(
0
)