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、Shipments of goods from China. B、Detection trees. C、The seeds from ash trees. D、The invasion of the emerald ash borer. D
A、Shipments of goods from China. B、Detection trees. C、The seeds from ash trees. D、The invasion of the emerald ash borer. D
admin
2019-03-17
40
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、Shipments of goods from China.
B、Detection trees.
C、The seeds from ash trees.
D、The invasion of the emerald ash borer.
答案
D
解析
转载请注明原文地址:https://kaotiyun.com/show/5pH7777K
0
大学英语六级
相关试题推荐
A、TheU.S.itselfhasproducedmoreoiloverthelastsixyears.B、Saudi,NigerianandAlgerianoilhavelosttheirmarketinA
A、Youaredeceived.B、Youaretargeted.C、Youaretracked.D、Youaredisappointed.C
A、Herwell-preparedspeech.B、Hermotivationandinterest.C、Heruniquemusicbackground.D、Hergoodexplanations.C男士说他认为女士的音乐背
A、Itisdesignedforjuniorschoolstudents.B、Itcontainsdifferentsubjectsexceptmaths.C、Eachcoursetakes40hourstocomp
A、Theyaretoofarawayfromtheearth.B、Ourskinisimmunetotheradiation.C、Theozonosphereprotectsusfromit.D、Thetree
A、Bytravellingwithawoman.B、Bywaitinginaqueue.C、Bymeetingdifferentpeople.D、Bygivingothersahand.A女士问男士如果他跟一个女的旅
A、Routineoperationshavebecomecomplex.B、Largeamountsoftaxmoneyarewasted.C、Manyinfectionsarenolongercurable.D、An
A、Ratherdifficulttoplease.B、Rudetowomendrivers.C、Talkativeandgenerouswithtips.D、Differentinpersonality.D①形容词选项,多
A、Itispartoftheirlocalheritage.B、Itisanattractionoftourists.C、Itistherevivalofmorals.D、ItisthemiracleofG
随机试题
社会主义初级阶段基本路线最主要的内容是()
A、窦性心律,心房频率<60次/minB、窦性心律,心房频率>100次/minC、窦性心律,P—P间期变化>0.12sD、房性心律,心房频率160次/minE、室性心律,心室频率180次/min窦性心律不齐
从中药中提取对热不稳定的成分,宜选用的方法是
以下哪项不是H1受体阻滞药的药理作用
下列哪些人员可以成为兼职执业律师?()
关于投资性房地产的初始计量,下列说法中,不正确的是()。
年报应于年度终了后()报出。
某城市共有A、B、C、D、E五个区,A区人口是全市人口的5/17,B区人口是A区人口的2/5,C区人口是D区和E区人口总数的5/8,A区比C区多3万人。全市共有多少万人?()
关于法律规则与法律条文的关系,下列表述中正确的是()。
A、Shebuiltamodelaweekago.B、Shecompletedhermodelquickly.C、ShehelpedhimonThursday.D、Shethoughtshecouldreduce
最新回复
(
0
)