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、The use of insecticides should be limited and controlled. B、A combination of some insecticides should be used at the same time
A、The use of insecticides should be limited and controlled. B、A combination of some insecticides should be used at the same time
admin
2013-06-02
52
问题
Scientists have observed that plants themselves produce many poisonous chemicals for defence 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 use less 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 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 eat our crops.
选项
A、The use of insecticides should be limited and controlled.
B、A combination of some insecticides should be used at the same time.
C、New insects should be introduced to mate with those that have survived from a certain kind of insecticide.
D、New kinds of insecticides should be explored and developed.
答案
D
解析
转载请注明原文地址:https://kaotiyun.com/show/pfB7777K
0
大学英语六级
相关试题推荐
Muchtimeandefforthasbeendedicatedtoresearchingthementalhealthbenefitsofflexibleworkenvironments.Butcantheabi
Muchtimeandefforthasbeendedicatedtoresearchingthementalhealthbenefitsofflexibleworkenvironments.Butcantheabi
A、Runninggetsapersonwetterwhileraining.B、Runningfastkeepsapersontotallydrywhileraining.C、Runninghasalittleim
ReturningtoScienceTeresaGarrettwasworkingpart-timeasabiochemistrypostdoc(博士后).Shehadaninfantathome,andsh
Mostvolcanoesarequiet.Theyrest【B1】_____forhundredsofyears.Noonepaysmuchattentiontothem.MountSt.Helenswason
Mostvolcanoesarequiet.Theyrest【B1】_____forhundredsofyears.Noonepaysmuchattentiontothem.MountSt.Helenswason
A、Thechairpersonelectedbythemembersofthecommittee.B、Oneoftherepresentativeswhoareinchargeofthegreatgraduatio
A、Toestablishagoodimageandahighreputation.B、Tosmoothlypresenttheirresultsandresearch.C、Tomakethemselvesconfid
A、Ajoblisting.B、Apersonalresume.C、Apermissionslip.D、Asalaryrequirement.B①细节题。文中提醒学生咨询时besuretobringaresume(一定要带
A、Inthevolcanoes.B、Onthefloorofthesea.C、Undertheriverbed.D、Atthefootofthemountains.A细竹推断题。文中指出数百万年前。钻石被强烈的火山
随机试题
大道之行也天下为公选贤与能讲信脩睦故人不独亲其亲不独子其子使老有所终壮有所用幼有所长矜寡孤独废疾者皆有所养男有分,女有归。货恶其弃于地也,不必藏于己。力恶其不出于身也,不必为己。是故谋闭而不兴,盗窃乱贼而不作。故外户而不闭,是谓大同。《礼记·礼运·大同》
A.阵发性剑突下钻顶样疼痛伴呕吐B.突发性上腹剧痛伴腹膜刺激征C.外伤后剧烈腹痛伴休克D.上腹部绞痛伴畏寒、发热E.腹痛呕吐便闭,肠鸣音亢进或消失肝脾破裂()
护理质量控制和监测评价的指标有
在小儿年龄分期中,幼儿期是指
关于免疫对机体的叙述正确的是()
不能制止同事违规行为的要及时报告()。
为了改变传统课程过分强调学科本位的现象,新课程注重联系学生经验和生活实际,提倡和追求不同学科间的彼此关系,这体现的新课程的结构特征是()。
设y=f(x)是由方程确定的函数,且满足f(1)=1.求曲线y=f(x)在点(1,1)处的曲率;
Large,multinationalcorporationsmaybethecompanieswhoseupsanddownsseizeheadlines.Buttoafargreaterextentthanmos
Itwasaboldideatobuildapowerstationinthedeepvalley,butit______aswellaswehadhoped.
最新回复
(
0
)