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
2016-04-02
29
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. [19]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. [21]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.
19. How far do the insects spread northward?
20. Why is part of the bark cut away?
21. 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
短文说,实验室对种子进行检查和照x-ray,确保没有钻孔虫的受精卵,只有最好的才被保存起来。故答案是B。从选项可以初步猜测题目与措施有关。“Only”表明文章要提出特殊的要点了,要提高警惕。
转载请注明原文地址:https://kaotiyun.com/show/seL7777K
0
大学英语六级
相关试题推荐
TryingtooHardCanSlowNewLanguageDevelopmentA)Neuroscientistshavelongobservedthatlearningalanguagepresentsadiffe
Asenseofselfdevelopsinyoungchildrenbydegrees.Theprocesscanusefullybethoughtofintermsofthegradualemergence
A、Becausethewaterpressureisgreaterthanairpressure.B、BecausethefirstCometscrashedinthewater.C、Becausethereisl
A、Anattorney.B、Ahealthcareconsultant.C、Atownplanner.D、Abeautician.A由男士提到的I’malawyer可知,男士是个律师,故答案为A)。
A、AskJoetoapologizetotheprofessorforher.B、Skiptheclasstopreparefortheexam.C、Telltheprofessorshe’slostherv
A、Walkingthedog.B、Cuttingthegrass.C、Takingcareofthechildren.D、Feedingthefish.C细节题。Marsha照看房子的时候要修剪草坪,给植物浇水,Eric托管房
A、Itispartoftheirlocalheritage.B、Itisanattractionoftourists.C、Itistherevivalofmorals.D、Itisthemiracleof
A、Itwasmorerespected.B、Itwasusedbymorepeople.C、Itwasvandalizedbytourists.D、ItquicklydeterioratedagainafterLi
A、Itispartoftheirlocalheritage.B、Itisanattractionoftourists.C、Itistherevivalofmorals.D、ItisthemiracleofG
随机试题
(2008年4月)企业不同层次的管理人员所从事的管理工作具有普遍性,但层次不同其侧重点亦不同,其中高层主管侧重于______。
男性,65岁,有慢性便秘多年。近半年来发现站立时阴囊部位出现肿块,呈梨形,平卧时可还纳。体检发现外环扩大,压迫内环嘱患者咳嗽,指尖有冲击感,平卧回纳肿块后,手指压迫内环处,站立咳嗽,肿块不再出现。术后当天患者宜采用的体位是
取某生物碱药物约0.5g,加对二甲氨基苯甲醛5mg、冰醋酸0.2ml与硫酸0.2ml,混匀,即显绿色,再加冰醋酸则变为红色。该药物应为
鉴别阳黄与阴黄。
在CO和N2分子之间存在的分子间力有:
全国银行间市场买断式回购交易的有关规则:买断式回购的期限由交易双方确定,但最长不得超过( )天。
民事诉讼中,当事人的申请符合下列情形之一的,人民法院应当再审( )。
纳税人在下列情形下,税务机关有权核定其应纳税额的有()。
有三种人才:能够独立做好事情的,能够带领好一个团队的。能够制订好的决策的。你认为自己属于哪一类?以后还需要在哪些方面努力?
当______成立时,称X→Y为平凡的函数依赖。
最新回复
(
0
)