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
31
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
regularly
解析
转载请注明原文地址:https://kaotiyun.com/show/OZZK777K
0
大学英语六级
相关试题推荐
DISCLAIMER:Thise-mailisconfidentialandshouldnotbeusedbyanyonewhoisnottheoriginalintendedrecipient(收件人).Ifyo
Rockwatch—TheBestClubonEarthIfyouareayoungpersonandinterestedingeology(地质学),thenRockwatchistheclubfory
Itis(reason)______forparentstopayfortheirchildren’seducation.
TheBeijingPeaceInternationalHotelWeoffertravelersawealthoffeaturesthatpromptreturnvisit.EASYACC
A、Afashiondesigner.B、Abankclerk.C、ATVhost.D、Asalesmanager.A信息明示题。对话中,男士询问女士想做什么工作,女士回答说想成为一名时装设计师,她认为这种工作更有创意,由此确定A)
A、Thefirstfloor.B、Thesecondfloor.C、Thethirdfloor.D、Thefourthfloor.D本题的问题关键词是whichfloor。对话中Mr.Gordon住3楼,Mr.Smith住在他
Themotherdidn’tknow______toblameforthebrokenglassasithappenedwhileshewasout.
ScienceFictionAmongthemostpopularbooksbeingwrittentodayarethosewhichareusuallyclassifiedassciencefictions.
A、Itisasimportantasthatfrombooks.B、Itislessimportantthanthatfrombooks.C、Itismoreimportantthanthatfrombook
A、Shethinksthatheshouldplanhismoneymorecarefully.B、Shethinksthatheshouldbuyaconvertible.C、Shethinksthathes
随机试题
唐某,女,73岁,跌伤致股骨颈骨折,拒绝手术,行持续下肢牵引。此时应预防的主要并发症是()。
治疗暑入阳明型产褥中暑,应首选的方剂是
A.炔诺酮B.他莫昔芬C.缩宫素D.米非司酮E.甲睾酮属于避孕药物()
关于地役权的特征,下列叙述不正确的是()。
承包人完成质量保修任务后,由( )组织验收。
钻孔灌注桩施工时,导管使用前,要对导管进行检漏和(),以防导管渗漏。
根据《预防未成年人犯罪法》的规定,对未成年人犯罪一律不公开审理的年龄是()。
幼儿园课程评价
根据《国有土地上房屋征收与补偿条例》,作出房屋征收决定的市、县级人民政府对被征收人给予的补偿不包括()。
中共中央于1935年12月17日至25日召开的()是从第五次反“围剿”失败到全民族抗战兴起过程中召开的一次重要会议。它表明党已经克服“左”倾冒险主义和关门主义,不失时机地制定出抗日民族统一战线的新策略。
最新回复
(
0
)