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
考研
Until about four decades ago, crop yields in agricultural systems depended on (1)_____ resources, recycling organic matter, buil
Until about four decades ago, crop yields in agricultural systems depended on (1)_____ resources, recycling organic matter, buil
admin
2010-06-17
30
问题
Until about four decades ago, crop yields in agricultural systems depended on (1)_____ resources, recycling organic matter, built-in biological control mechanisms and rainfall patterns. Agricultural yields were (2)_____ but stable. Production was (3)_____ by growing more than one crop or variety in space and time in a field as insurance against pest (4)_____ or severe weather. Inputs of nitrogen were (5)_____ by rotating major field crops with legumes. In turn, rotations suppressed insects, weeds and diseases by effectively (6)_____ the life cycles of these pests. A typical corn belt farmer grew corn (7)_____ with several crops including soybeans, and small grain production was intrinsic to maintain livestock. Most of the labor was done by the family with occasional hired help and no (8)_____ equipment or services were purchased from off4arm sources. In these type of farming systems the link between agriculture and ecology was quite (9)_____ and signs of environment degradation were seldom evident.
But as agriculture modernization (10)_____ the ecology-farming linkage was often broken as ecological principles were (11)_____. In fact, several agricultural scientists have arrived at a (12)_____ consensus that modem agriculture confronts an environment crisis. A growing number of people have become concerned about the long-term (13)_____ of existing food production systems. Evidence has shown that (14)_____ the present capital-and-technology-intensive fanning systems have been extremely productive and competitive, they also bring a (15)_____ of economic, environmental and social problems.
Evidence also shows that the very nature of the agricultural structure and prevailing polices have led to this environmental (16)_____ by favoring large farm size, specialized production, crop monocultures and mechanization. Today as more and more farmers are integrated (17)_____ international economies, imperatives to (18)_____ disappear and monocultures are rewarded by economies of scale. In turn, lack of rotations and diversification (19)_____ key self-regulating mechanisms, turning monocultures into highly (20)_____ agro-ecosystems dependent on high chemical inputs.
选项
A、external
B、internal
C、exported
D、imported
答案
B
解析
考查上下文语义衔接。文章开头就讲以前农业的状况,从后面并列的"循环有机物质,内部生物控制机制和降雨机制",可以推测农业依赖的是内部资源,选internal,同时注意与本段倒数第二句谈到的 no...equipment or service were purchased from off-farm sources相呼应。排除external"外部的"、imported"进口的"、exported"出口的"。
转载请注明原文地址:https://jikaoti.com/ti/jwRRFFFM
0
考研英语一
相关试题推荐
Aneweconomicspaperhassomeold-fashionedadviceforpeoplenavigatingthestressesoflife:Findaspousewhoisalsoyourb
Writeanessaybasedonthefollowingbarchart.Inyourwriting,youshould1)interpretthechart,and2)giveyourcomments.
YawningcanbeaproblemattheofficeforLindsayEierman,whichmakesherembarrassed."I’veexplained,’I’msorry,Ididn’
[A]MonitorYourAlcoholUse[B]PayAttentiontoTableManners[C]Don’tBeaGossip[D]NetworkwithHigher-ups
UncertaintythreatenstheveryexistenceofQuinhagak,Alaska.Thevillageisbuiltonalayerofpermanentlyfrozenground,and
Universityusedtobeforaprivilegedfew.Insomecountriesitisnowalmostariteofpassage.Althoughthatisexcellentnew
Nameshavegainedincreasingimportanceinthecompetitiveworldofhighereducation.Ascollegesstriveformarketshare,they
Writeanessaybasedonthefollowingdrawing.Inyourwriting,youshould1)describethedrawingbriefly,2)explaintheinten
WhatisimpliedbutnotstatedinthefirstsentenceisthatAmericanIndians______.WhatistheattitudeofAmericanIndians
WhatisimpliedbutnotstatedinthefirstsentenceisthatAmericanIndians______.Itseemsthattheauthorismostcritical
随机试题
口腔健康教育的目的是
肝癌介入治疗术后穿刺侧肢体应制动的时间为
能杀灭所有微生物以及细菌芽胞的方法是
某行业的龙头企业A公司处于我国华东地区,为了制定自身的发展战略,采用五因素模型对行业的竞争结构进行分析。部分因素分析如下:(1)本行业的新进入者来自国内、国外两个方面。先进技术和研发投资是进入本行业的主要门槛;此行业在政策上受到一定限制;对于国外进入者,
更科学地衡量财政支出规模的指标是( )。
企业提取的盈余公积经批准可用于弥补亏损、转增资本、发放现金股利或利润。()
在德育中“一把钥匙开一把锁”贯彻了哪条原则()
总体看来,2004年世界各国的石油探明储量基本变化不大。但是由于BP公司修正了前苏联、哈萨克斯坦、伊朗、利比亚和苏丹等国的数据,特别是哈萨克斯坦从12亿吨修正到54亿吨,从而使各国在全球石油储量分布中所占的比例发生了一些变化。尽管如此这并没有影响到欧佩克在
算法的空间复杂度是指()。
Managementjargoncanalienatestaffandleavebosseslookinguntrustworthyandweak,accordingtoasurveypublishedonMonday
最新回复
(
0
)