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
2013-06-15
28
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 The emerald ash borer has destroyed trees in the Midwest and as Far East in the United States as Maryland. 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. 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. 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. [31]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.
29. How far do the insects spread northward?
30. Why is part of the bark cut away?
31. 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
短文说,钻孔虫是在树上产卵,孵出的幼虫钻到内层树皮吸取营养,故把部分树皮削去会使树更容易成为攻击的目标,当钻孔虫来袭时就能有所发觉。故C是正确答案。从选项可以初步猜测题目与树木和昆虫有关。解题时需听清楚问题问的是什么。
转载请注明原文地址:https://jikaoti.com/ti/TxbFFFFM
0
大学英语六级
相关试题推荐
A、Peoplecanusenearly75percentofit.B、Peoplecanuseabout97percentofit.C、Peoplecanuseexactly3percentofit.D、P
A、Hehasbeeninabadmoodsincehegotup.B、Theweatheraffectedhim.C、Hedoesn’tliketotalktopeople.D、Hedoesn’taska
A、Itwasmild.B、Itwashumid.C、Itwashot.D、Itwascool.C事实细节题。预读选项可知,问题问的是过去某时的天气状况。听音关键是要分清楚他们对每年夏天的不同描述。根据女士对第一个夏天的描述“华氏
A、Hethinksthewomanshouldn’tspeaksoopenly.B、Hetotallyagreeswiththewoman.C、Hewantstopersuadethewomannottothi
A、Thereisdangerofaccidentsontheline.B、Thereisnodangerofaccidentsontheline.C、Theirspeedswillbeautomatically
12ThingsI’veLearnedFromTravelingAroundtheWorldforThreeYearsOnMarch13,2007,Ihandedoverthekeystomyhouse
Notsolongago,predictionmarkets(市场预测)werebeingconsideredasafantasticnewwaytoforecasteverythingfromthecompleti
HealthHealthcouldbedefinedtheoreticallyintermsofcertainmeasuredvalues;forexample,apersonhavingnormalbodyt
HecleanedtheglassesCarefully__________________(以免它被弄坏了而变得不保暖).
A、Themanisaforgetfulperson.B、Thetypewriterisnotnew.C、Themancanhavethetypewriterlater.D、Themanmisunderstoodh
随机试题
单层厂房纵向连系构件包括()。
蛛网膜下腔出血后脑血管痉挛的高峰时间是.
凉燥与温燥的鉴别点是
患儿,男,8个月。因多汗,易惊2个月就诊,患儿近2个月来,明显多汗,入睡后更明显,并且有入睡困难,易惊,表现为稍有声响即惊醒,并哭闹不止。患儿为早产儿,人工喂养,至今未加辅食。佝偻病颅骨软化症出现于
下列逻辑代数基本运算关系式中不正确的是()。
下列属于进口货物关税完税价格组成部分的是()。(2015年)
行政层级式组织形式在()环境中最为有效。
会计的基本职能是()。
某幼儿园的美术课上,曾老师指导学生把天然的竹根须做成卷曲的头发,还演示如何借助竹节的弧度制成黄包车的顶棚。这表明曾老师具有()。
市场组合包含两种股票,股票U和V,二者的收益率相互独立。股票U的价格为60美元,股票V的价格为40美元。股票U和V的期望收益率分别为7.90%和18.15%。股票U的标准差为18%,股票V的标准差为42%。计算市场组合的期望收益率和标准差。
最新回复
(
0
)