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
86
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
A、SetinhernativeHuronCountyinsouthwesternOntario.B、SoutheastcountiesofCanada.C、TheuniversitywhereshestudiesEng
Textinghaslongbeenbemoaned(哀叹)asthedownfallofthewrittenword,"penmanshipforilliterates,"asonecriticcalledit.
Anewalcoholdetectionsystemcouldbeintroducedincarsby2020,preventingintoxicated(喝醉的)driversfromstartingtheircars.
Anewalcoholdetectionsystemcouldbeintroducedincarsby2020,preventingintoxicated(喝醉的)driversfromstartingtheircars.
Ourbodiesexperienceanebbandflowofenergythroughouttheday.Thisiscalledacircadianrhythm,andithasbeenstudied【C
Ourbodiesexperienceanebbandflowofenergythroughouttheday.Thisiscalledacircadianrhythm,andithasbeenstudied【C
Farmersusuallyuseploughstopreparetheirfieldsforplantingcrops.Ploughscutintotheground,andliftupweeds,andothe
Theincreaseinglobaltrademeansthatinternationalcompaniescannotaffordtomakecostlyadvertisingmistakesiftheywantt
A、Thesouptastesverybad.B、Thesoupistooexpensive.C、Thesocksareoflowquality.D、Thesocksgivewrongmessage.D录音提到,这
A、Itisworthwhile.B、Itistooexpensive.C、Ittastesdelicious.D、Itishealthier.B
随机试题
()抽油机下行(下冲程)时,固定阀是关闭的,游动阀是开的,悬点(光杆)所受静载荷为:抽油杆(柱)在液体中重。
下列以碳酸氢钠与枸橼酸为崩解剂的是
男孩,7岁,查体合作,跛行步态明显,左髋屈曲、外展、外旋位畸形,左下肢肌肉萎缩。诊断时首先应进行
(2004)中小学南向的普通教室冬至日底层满窗日照时间不应小于()。
根据《水利水电工程标准施工招标文件》,除专用合同条款另有约定外,现场测量基本控制点、基线和水准点应由()提供。
会计核算软件按照不同的适用范围可分为通用会计核算软件和商品化会计核算软件。()
读下列A、B两工业区示意图,回答问题。A、B两图中___________是我国的辽中南工业基地,该地区___________、___________等矿产资源丰富。你能列举几种该工业基地的主要工业部门吗?(至少说出三种)___________;___
下列句子中有语病的一句是()。
为保护中农利益,《兴国土地法》对《井冈山土地法》进行的一个原则性改动是()。
Accordingtothepassage,Chinaisaleadingbuyerof_________.
最新回复
(
0
)