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
Scientists have discovered that plants themselves produce many poisonous chemicals for (36)______ against insects. But insects h
Scientists have discovered that plants themselves produce many poisonous chemicals for (36)______ against insects. But insects h
admin
2009-04-23
91
问题
Scientists have discovered that plants themselves produce many poisonous chemicals for (36)______ against insects. But insects have developed ways of (37)______ with them and, in fact, have been eating plants for about 250 million years. Now insects are using these same (38)______ to deal with man-made poisons—insecticides. This is why (39)______ of insects to insecticides has developed so (40)______.
What should be done? Scientists studying the problem suggest that farmers use less insecticides. At the moment, farmers (41)______ spray crops as a (42)______ against problems that are caused by large number of pests. They should, instead, spray only where pests have actually been seen. Secondly, farmers could use a (43)______ of two or three insecticides at once. (44)____________.
The most surprising suggestion, perhaps, is that at certain times of the year, (45)____________. The new insects will mate with those which survived from a certain kind of insecticide and will lessen the latter’s resistance to it.
(46)____________ , which may be resistant to all poisons invade our farms and devour our crops.
Scientists have discovered 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—insecticides. This is why resistance of insects to insecticides has developed so rapidly
What should be done? Scientists studying the problem suggest that farmers useless insecticides. 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 insecticides at once. To survive, the insects would need to become resistant to two or more insecticides at the same time.
The most surprising suggestion, perhaps, is that at certain times of the year, farmers should actually try to attract insects onto the crops they are trying to protect. The new insects will mate with those which survived from a certain kind of insecticide anti will lessen the latter’s resistance to it.
Scientist 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 poisons invade our farms and devour our crops.
选项
答案
precaution
解析
转载请注明原文地址:https://kaotiyun.com/show/dZZK777K
0
大学英语六级
相关试题推荐
Weadmirehimforhisambitiontobecomeafirst--ratescholarinAmericanStudies.
A、Repairthewoman’scomputer.B、Fixhisowncomputer.C、Haveathree-dayholiday.D、Visitthewomanthenextday.A题目询问男士将要做什么。
Americansdependontheircarsmorethananyotherpeople.Thefamilycarhasbeenacommonthingsincetheearly20thcenturya
A、Bythelastname.B、Bythefirstname.C、Bythemiddlename.D、Bythefullname.B题目询问美国人在公司如何相互称呼。女士问美国人之间怎么问候(greet)对方,男士说:“
Allanislookingforwardto______hisAmericanpartneratthetradefair.
A—AirpollutionB—AirqualityC—AlternativeenergysourcesD—CarbonemissionsE—CarbonfootprintF—ClimatechangeG—Electricveh
A、TakeaChinesecourse.B、VisitChina.C、Stayathome.D、Gotoasummercamp.B本题询问迈克尔今年夏天最有可能做什么。男士说I’mgoingtoChina...(我将去中
Goodevening,ladiesandgentlemen!Firstofall,letmethankyoufor【T1】_____ustosuchagreatChristmasparty.We【T2】_____the
A、Hethinksitisratherhot.B、Hethinksitisreallywarm.C、Hethinksitisnotwarm.D、Hethinksitisverycomfortable.AW:
A、Trafficlawsandregulations.B、Drivingtheoryandpractice.C、Switchinglanesandturningcorners.D、Waystoavoidtrafficac
随机试题
珠光体和莱氏体是一种单相组织。
设x是方程x+y—z=ez所确定的x与y的函数,则dz=______.
女,20岁,上腹隐痛1年余,纳差,结合图像,最可能的诊断为
采用伊红Y染色观察精子存活率,死亡精子的特点是
中华民国北京政府设立的最高司法审判机关是()。
证券公司自营业务违反《刑法》规定的行为不包括()。
中国证券登记结算有限责任公司在结算系统中设立()用于完成与结算参与人资金和证券的交收。Ⅰ.资金集中交收账户Ⅱ.证券集中交收账户Ⅲ.交收担保品证券账户Ⅳ.专用待清偿证券账户
隐性课程与显性课程相伴而生,对显性课程的教育效力起着积极地影响。()
稻谷:大米
PaulaJones’caseagainstBillClintonisnow,forallpossiblepoliticalconsequencesandcapacityformediasensation,afairy
最新回复
(
0
)