2. 考研
  3. 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

admin2010-06-17  77
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、diversion
B、diversity
C、disease
D、specialization
答案B
解析 考查上下文语义衔接和近义词辨析。该选项所在的句子包括三个并列的小句，讲了现代化农业的经营，意思上也是顺承的关系，从前面的句子和后面的句子可以推断该选项的意思。另外，下面句中diversification也是对该选项的一个重要提示，不过名词词形变化了。diversity是"多样性"，符合文意；而diversion意思是"转移，转换"，disease是"疾病"，specialization是"特殊化，专门化"。
转载请注明原文地址:https://kaotiyun.com/show/8u44777K
0

考研英语一

相关试题推荐
随机试题
最新回复(0)