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
64
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
to survive,the insects would need to become resistant to two or more insecticides at the same time.
解析
转载请注明原文地址:https://www.kaotiyun.com/show/ZZZK777K
0
大学英语六级
相关试题推荐
AbouthowmanyadultAmericanshavethe"weightproblem"?______percent.
PartyBhastherighttocancelthecontractwithawrittennoticetoPartyAunderthefollowingconditions.
Ibelievemyeducation,trainingandpersonalqualitiesmeettherequirementsyousetforthepositionofelectricalengineer.
Thispartistotestyourabilitytodopracticalwriting.Youarerequiredtowriteabusinessletteraccordingtothefollowin
Wearesurethatwe______oursecondprojectbytheendofthenextmonth.
WelcometoLondon!Withover80stops.3mainsightseeingroutesandcountlessphotoopportunities.TheOriginalTourreallyis
FairwayKenwoodisaqualityPrivateHireCarServicecompany.Thecompanyhasalongandestablishedservicehistorywithover
ScienceFictionAmongthemostpopularbooksbeingwrittentodayarethosewhichareusuallyclassifiedassciencefictions.
Thispassagegivesageneraldescriptionofwhyrecessionsoccurandhowtheymakeacountry’seconomyworse.Bymanipulating_
A、Thehomeownerisafraidofbeingaccused.B、Thehousesitterpleadsagainandagain.C、Mosthousesittersareverypoor.D、The
随机试题
A.水肿仅限于踝部B.水肿限于踝部和小腿C.水肿延及大腿D.水肿延及外阴和腹部E.全身水肿或伴腹水水肿“++++”是指
应激时糖皮质激素持续分泌增加会产生的不利影响是
可在心尖部听到病理性第四心音的疾病不包括
下列哪几种疾病是骨髓移植的适应证
营养性巨幼细胞性贫血的病因是
在当事人提出请求的情况下,下列哪些案件应当适用听证程序?()
按浸水条件的不同,沥青混合料马歇尔稳定度试验有()。
(深圳2012—10)一个长方形周长130厘米,如果它的宽增加,长减少,就得到一个相同周长的新长方形,则原长方形的面积为()平方厘米。
数据通信中数据传输速率是最重要的性能指标之一,它指单位时间内传送的二进制数据位数,常用的单位是________。
WelcometoVirginiaPleasecometofeelthewarmthofaVirginiawelcomefromtheBlueRidgeMountainstotherollingAtlant
最新回复
(
0
)