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
36
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
farmers should actually try to attract insects onto the crops they are trying to Protect
解析
转载请注明原文地址:https://kaotiyun.com/show/4ZZK777K
0
大学英语六级
相关试题推荐
Manypeoplewholiveincitiessaythattheydislikecitylife.Theysaythecityisnoisy,dirtyandcrowded.Theyaretiredof
Manypeoplewholiveincitiessaythattheydislikecitylife.Theysaythecityisnoisy,dirtyandcrowded.Theyaretiredof
NoticeOverthepastmonththePersonnelOfficehasreceivednumerouscallsabouttheapprovalprocessforusingthenew"fl
Wewereallexcitedatthenews______ourannualsaleshadmorethandoubled.
Iftheengineistobeshutdownforalongtime,werecommendthefollowingmeasuresfortheenginetoavoidcorrosion.
TheBeijingPeaceInternationalHotelWeoffertravelersawealthoffeaturesthatpromptreturnvisit.EASYACC
FairwayKenwoodisaqualityPrivateHireCarServicecompany.Thecompanyhasalongandestablishedservicehistorywithover
Whatisthepassagemainlyabout?IntheUSNurses’HealthStudy,womenwhosleptanaverageof7hoursanight______.
A、Aperiodwhencarsarerushingontheroads.B、Aperiodwhenpeoplearegoingtoorfromtheirwork.C、Aperiodwhencarsare
A、Ashortperiodoffairweatherandmilddays.B、Nodefinitetimeofbeginningorending.C、Itsendsignalswinter’sstart.D、S
随机试题
企业进行筹资决策时,主要是通过平衡资本成本和()来选择资金来源的最佳结构。
麻醉诱导和苏醒速度最快的吸人麻醉药是
健康教育诊断中的社会诊断的重点内容包括()
骨纤维异常增生症的特点是
口腔内牙石沉积最多的牙位是
患者,女,46岁。口渴自汗,心悸失眠,多梦,久泻不止,以晨起腹泻为主,舌偏红少津,脉虚。用药宜首选
航空公司实行的“经常乘客计划”,是________。
设伦敦外汇市场即期汇率为1英镑=1.4608美元,3个月美元远期外汇升水0.51美分。则3个月美元远期汇率为()。
MostbanksintheU.S.openat9:00a.m.or10:00a,m.andclose(41)3:00p.m.and5:00p.m.,butstayopenlateronFrid
Lifereallyshouldbeonelongjourneyofjoyforchildrenbornwithaworldofwealthattheirfeet.Internationallyfamous
最新回复
(
0
)