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
72
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://www.kaotiyun.com/show/4ZZK777K
0
大学英语六级
相关试题推荐
说明:以部门经理(RuthCrawford)的名义给公司全体员工发一份内部通知。时间:2015年4月10日事由:有关更换电话系统事宜内容:1.由于业务需要,公司拟更新目前使用的电话系统;2.现有3个通讯公司提交的更新方案,内容见附件;3.请员
ThisATMhasbeenoutofserviceforafewdays.Itshould______lastweek.
(Website)VisitorAgreementStatesman.comisprovidedtoyoubyCoxTexasNewspapers.Thisvisitoragreementislegallybind
HegotamessagefromMissZhang______ProfessorWangcouldn’tseehimthefollowingday.
LadiesandGentlemen,WelcometoLondonInternationalLanguageCenter.WeteachEnglishforboth【T1】______andbusinesspurpo
A、Ateacher.B、Adoctor.C、Asecretary.D、Asalesman.D此题询问男士的工作是什么。从男士的回答可知他是一个销售员(asalesman),因此本题答案为D项。
Americansdependontheircarsmorethananyotherpeople.Thefamilycarhasbeenacommonthingsincetheearly20thcenturya
A、Bythelastname.B、Bythefirstname.C、Bythemiddlename.D、Bythefullname.B题目询问美国人在公司如何相互称呼。女士问美国人之间怎么问候(greet)对方,男士说:“
Fewpeoplewouldeverthinkofbeginninganewjobwhentheyareold,butAnnadiditattheageof76.Shewas【T1】______inapo
Whatisthepassagemainlyabout?Whatdoestheauthorsayabouttheeffectofnicotineonsmokers?
随机试题
南京国民政府的五院中,属于最高监察机关的是()
结核杆菌感染见于金黄色葡萄球菌感染见于
博美犬,雌性,4岁,正常免疫。食入多量红薯后出现呕吐,次日呕吐加剧,第三日就诊,体温38℃,拱背,鼻干,精神差;血常规检查白细胞数56.3×109,红细胞4.97×1012,血红蛋白140g/L。进一步诊断,血清生化检查,淀粉酶活性为3512U/L,该
含油脂多的饮片易
每年霜降后,明朝三法司会同公、侯、伯审理重囚的制度称:()
()是指上市公司高管人员,控股股东、实际控制人和行政审批部门的知情人员,利用工作之便在公司并购、业绩增长等重大信息公布之前,泄露信息或利用内幕信息买卖证券谋取私利的行为。
用配方法把二次型一2x1x2+2x1x3-2x2x3化为标准形,并写出所用坐标变换.
Weoftentendtoassociatesmilingastheresultofapositiveeventormood.Butresearchdemonstratesthattheactofsmiling,
在Oracle数据库系统中,可以建立一种称为聚簇(cluster)的结构,这是为了
Inourtimeitisbroadlytruethatpoliticalwritingisbadwriting.Whereitisnottrue,itwillgenerallybefoundthatthe
最新回复
(
0
)