One basic weakness in a conrvation system bad wholly on economic motives is that most members of the land community have no economic value. Yet the creatures are members of the biotic community and, if its stability depends on its integrity, they are entitled to continuance.
When one of the noneconomic categories is threatened and, if we happen to love it, we invent excus to give it economic importance. At the beginning of the century songbirds were suppod to be disappearing.(46)Scientists jumped to the rescue with some distinctly shaky evidence to the effect that incts would eat us up if birds failed to control them. The evidence had to be economic in order to be valid.
It is painful to read the roundabout accounts today. We have no land ethic yet, (47) but we have at least drawn nearer the point of admitting that birds should continue as a matter of intrinsic right, regardless of the prence or abnce of economic advantage to us.
A parallel situation exists in respect of predatory mammals and fish-eating birds. (48) Time was when biologists somewhat overworked the evidence that the creatures prerve the
health of game by killing the physically weak, or that they prey only on “worthless” species. Here again, the evidence had to be economic in order to be valid. It is only in recent years that we hear the more honest argument that predators are members of the community, and that no special interest has the right to exterminate them for the sake of a benefit, real or fancied, to itlf.
Some species of tree have been“read out of the party” by economics-minded foresters becau they grow too slowly, or have too low a sale value to pay as timber crops.(49) In Europe, where forestry is ecologically more advanced, the noncommercial tree species are recognized as members of native forest community, to be prerved as such, within reason. Moreover, some have been found to have a valuable function in building up soil fertility. The interdependence of the forest and its constituent tree species, ground flora, and fauna is taken for granted.
To sum up: a system of conrvation bad solely on economic lf-interest is hopelessly lopsided. (50) It tends to ignore , and thus eventually to eliminate, many elem
ents in the land community that lack commercial value,but that are esntial to its healthy functioning. It assumes, fally, that the economic parts of the biotic clock will function without the uneconomic parts.
文章分析：
本文节选自美国生态学家Aldo Leopold 的著作《沙郡年纪》（A Sand Country Almanac）中的“土地伦理”部分。作者认为，完全基于经济动机和利己主义的环保体系是极不可取的。本文语言优美，句子形式多样，主要考察的知识点包括：固定结构、各类从句、从句并列、被动语态、根据上下文选择此意。
语篇分析：
第一段：开门见山提出作者的林甸，及完全基于经济动机和利己主义的环保体系是极不可取的。
第二段-第四段：以百灵鸟、肉食动物和食鱼鸟类为例，说明过去人类总要利用经济方面的证据来保护一些没有经济价值的物种，而现在人类有了正确的观点。
第五段：以一些种类的树木为例，说明现在没有经济价值的物种也得到了合理的保护。
第六段：呼应首尾，总结观点。
第一段：
One basic weakness in a conrvation system bad wholly on economic motives is that most members of the land community have no economic value.
译文：在一个完全以经济目标为基础的（生态）保护系统中，一个基本的弱点在于陆地群落的大多数成员没有经济价值。
conrvation | n.保存,保护,保守;守恒,不灭 |
conrvative | a.保守的,守旧的 n.保守主义者 |
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句式结构分析：One basic weakness [in a conrvation system (bad wholly on economic motives)] is that most members of the land community have no economic value.
②Yet the creatures are members of the biotic community and, if its stability depends on its integrity, they are entitled to continuance.
rewarding
译文：但是这些生物是生物群落的成员，并且如果生物群落的稳定性依赖其完整性，那么这些生物有权继续生存。
creature | n.人,动物;生物 |
create | v.创造,创作;引起,造成,建立 |
creative | a.有创造力的,创造性的 | beyonce knowles
biotic | a.关于生命的，生物的jillian murray |
biography | n.传记；传记文学 |
biology | n.生物学 |
integrity | n.正直,诚实;完整,完全 |
intact | a.完整无缺的,未经触动的,未受损伤的 |
英汉词典在线翻译integral | 2008年奥运会主题曲a.构成整体所必需的;完整的 |
integrate | v.(into,with)(使)成为一体,(使)结合在一起 |
depend on | 依赖，依靠 |
entitle | v.给以权利(或资格);给…称号(题名);授权 |
be entitled to | 赋予...的权利，称号 |
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第二段：
When one of the noneconomic categories is threatened and, if we happen to love it, we invent excus to give it economic importance.
译文：当一种无经济价值的物种受到威胁时，并且如果我们正好喜欢它，我们就会编造理由来赋予其经济价值。
category | n.种类，部属，类目；范畴，类型 |
threaten | v.恐吓,威胁;有…危险,快要来临 |
threat | n.恐吓,威胁;坏兆头,危险迹象 |
noneconomic | A. 非经济价值的 |
economic | a.经济(上)的,经济学的 |
economical | a.节约的,经济的 |
economics | n.经济学,经济情况 |
economy | n.节约;经济 |
| | 小学三年级英语课件
句式结构分析：When one of the noneconomic categories is threatened and, if we happen to love it, we invent excus to give it economic importance.
if 引导插入语成分，when为时间状语，主句结构为we invent
②At the beginning of the century songbirds were suppod to be disappearing.
译文：在本世纪初，鸣禽本被认为正趋向灭绝。
be suppod to do 应该。。。
③Scientists jumped to the rescue with some distinctly shaky evidence to the effect that incts would eat us up if birds failed to control them. The evidence had to be economic in order to be valid.
rescue | v./n.营救,援救 |
distinctly | adv. 截然不同地 |
distinct 贝乐学科英语怎么样 | a.清楚的,明显的;(from)截然不同的 |
distinction | n.区别,差别;级别;特性;声望;显赫 |
distinguish | v.(from)区别,辨别;辨认出;使杰出 |
evidence | n.明显;显著;根据;证据;迹象 |
evident | dinnerware a.明显的,明白的 |
小码王valid | a.有效的;有根据的;正当的 |
invalid | n.病人,伤残人 a.有病的,伤残的;无效的 |
jump to | 急忙做某事 |
to the effect | 大致意思是 |
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译文：科学家们急忙前来挽救这一局面，他们所使用的证据显然站不住脚，其大意是，如果鸟类未能控制昆虫，昆虫将会吞噬我们。为使证据有效，其必须与经济相关。vicky
