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、There are 250 million plants eaten by insects. B、There are fewer plants than 250 million years ago. C、They have their way of g
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 g
admin
2013-01-20
33
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 studyilg the problem suggest that farmers use less insecticide.At the moment,famlers 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 jnsecticide 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,perhaps,is that,at certain times of the year,famers 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.
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,科学家发现庄稼自身可以产生许多有害的化学物质来抵御昆虫的侵害,即庄稼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:https://kaotiyun.com/show/Lbu7777K
0
大学英语四级
相关试题推荐
A、ChangesinChildRearing.B、ChangesinAmericanSexRoles.C、ChangesinMen’sRolesinFamilyLife.D、ChangesinWomen’sRoles
It’sbeen30yearssinceCongressrevisedUSpatentlawstoencourageuniversitiestoembracetheworldofcommerce.Criticspre
Lastyear’seconomyshouldhavewontheOscarforthebestpicture.Growthingrossdomesticproductwas4.1percents)profits
A、Policemananddriver.B、Programhostandguest.C、Polltakerandpassenger.D、Politicianandsupporter.C选项表明,本题考查对话双方之间的关系,故听
PerhapslikemostAmericansyouhavesomeextrapoundstoshed.Youmayevenhavetriedafad(时尚)dietortwo,butfoundyourse
A、Hedoesn’talwayslisten.B、Hehasanearinfection.C、He’snevermissedameeting.D、Hehastoattendanothermeeting.A对话中男士
Theholidaysareatimeforeating:piesatThanksgiving,chocolatesforAdventandoverflowinggiftbasketsofcookiesandcand
A、Staywhereheis.B、Gohometotelephonetheorder.C、Trytogettheticketselsewhere.D、Returnafterlunch.A选项均以原形动词开头及其中的h
Scandalsarerootedintest-basedsystems;theyexistwithorwithoutfraud.Wesellourchildrenshortwhenwesendthemtosch
Gettingajobcanbeespeciallydifficultforsomeonewithaprisonrecord.SoaprisontrainingprogramintheAmericanNorthwe
随机试题
阅读《早雁》一诗,回答问题:金河秋半虏弦开,云外惊飞四散哀。仙掌月明孤影过,长门灯暗数声来。须知胡骑纷纷在,岂逐春风一一回。莫厌潇湘少人处,水多菰米岸莓苔。“云外惊飞四散哀”这一句比喻了什么?
女,13岁,发热伴右大腿疼痛2周,查体:精神委靡,患肢呈半屈曲位,皮温高,右大腿远端有压痛。WBC:14×109/L,中性粒细胞占90%,股骨正侧位X线片可见干骺端骨质疏松及层状骨膜反应。可能性最大的诊断是
男性,患者。42岁。因十二指肠溃疡大出血住院,5小时内已输血600ml,测血压78/40mmHg、脉率124次/分,肠鸣音活跃,此时宜
哪些因素可增加患Alzheimer病的风险
《诗经.大雅.大明》中关于周文王娶妻“亲迎于渭,造舟为桥”的描述,是关于()的最早记载。
将考生文件夹下的所有自由表添加到“图书”数据库中。
设有如下代码:x=0Dox=x+1LoopWhilex>=____________运行程序,要求循环体执行4次后结束循环,在空白处填入适当语句。
A、 B、 C、 B本句是确定罗斯先生是否通知了会有更多的人参加研讨会这一消息的否定疑问句。
ThestudyfoundthatcigarettesmokingamongAmerican【36】______droppedduringthepastyear.Thedropcontinuesageneraldecre
Shesenthersontobedearlyasa(n)______forbreakingthewindow.
最新回复
(
0
)