首页
登录
职称英语
[originaltext] Scientists have observed that plants themselves produce many
[originaltext] Scientists have observed that plants themselves produce many
游客
2024-01-30
63
管理
问题
Scientists have observed that plants themselves produce many poisonous chemicals for defense against insects. But insects have developed ways of dealing with them and, in fact, have been eating plants for about 250 million years. Now insects are using these same mechanisms to deal with man-made poisons—insecticide. This is why resistance of insects to insecticide has developed so rapidly. What should be done? Scientists studying the problem suggest that farmers use less insecticide. At the moment, farmers regularly spray crops as a precaution against problems that are caused by large numbers of pests. They should, instead, spray only where pests have actually been seen. Secondly, farmers could use a combination of two or three insecticide at once. To survive, the insects would need to become resistant to two or more poisons at the same time. The most surprising suggestion, perhaps, is that, at certain times of the year, farmers should actually try to attract new insects onto the crops they are trying to protect The new insects will mate with those which survived from a certain kind of insecticide and will lessen the latter’s resistance to it.
Scientists hope that these and other measures will postpone the day when farmers and scientists will have to stand by while new super bugs which may be resistant to all our poisons invade our farms and devour our crops.
19 What does the speaker say about plants?
20 What is mentioned as one of the suggestions raised by scientists?
21 What is the most surprising suggestion scientists give?
选项
A、There are 250 million plants eaten by insects.
B、There are fewer plants than 250 million years ago.
C、They have their way of guarding against insects.
D、They have a better immune system than before.
答案
C
解析
短文开头就说到,科学家发现植物自身可以产生许多有害的化学物质来抵御昆虫的侵害,即植物自有抵制昆虫侵害的方法,C与此含义相符,故正确。
转载请注明原文地址:http://tihaiku.com/zcyy/3405916.html
相关试题推荐
[originaltext]Anewstudyfoundthat43percentofboyandgirlparticipant
[originaltext]Anewstudyfoundthat43percentofboyandgirlparticipant
[originaltext]Peoplewithbiggerbrainstendtoscorehigheronstandardte
[originaltext]Peoplewithbiggerbrainstendtoscorehigheronstandardte
[originaltext]Iliveinasmallvillageinthecountry.MywifeandIrunt
[originaltext]W:Goodafternoon,Mr.Burke.Didyouhaveagoodlunch?M:Yes,
[originaltext]W:Goodafternoon,Mr.Burke.Didyouhaveagoodlunch?M:Yes,
[originaltext]W:Goodafternoon,Mr.Burke.Didyouhaveagoodlunch?M:Yes,
[originaltext]M:Hello.Ineedtotalkwithsomeoneaboutmydriver’slicense.
[originaltext]M:Hello.Ineedtotalkwithsomeoneaboutmydriver’slicense.
随机试题
Changesinthetechnologyofcommunicationareoccurringsorapidlythatwe
Advertisingisdifferentfromotherformsofcommunicationinthattheadvertise
[originaltext]Areyouafraidtoraiseyourhandinclass,evenwhenyoukno
StopBeingaPeoplePleaser1.Say"no"■Givereasonsinsteadof【T1】______exc
下列行为中,属于检察院以渎职犯罪案件立案范围的是()A.虐待被监管人案 B.报
关于战略资产配置,以下理解错误的是()。A.是一种事前的规划和安排 B
( )是世界四大证券交易所之一,欧洲最大的证券交易所,历史可追溯至1801年。
与茵陈清湿热、退黄疸功效相关的药理作用中,不正确的是A.保肝 B.抗肿瘤 C
溶血反应病人出现黄疸和血红蛋白尿的原因是A:血红蛋白遇酸性物质变成结晶体,阻塞肾
某立井井筒工程,按我国现行建筑安装工程费用项目构成的合同总价为3000万元。部分
最新回复
(
0
)