passage 22 海洋环境没有陆地环境稳定

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文章讲解：

①Marine ecosystems certainly have less permanence than terrestrial ecosystems.[剑1] ②Ashore, ecologists are not confronted with shifting ecological discontinuities, or with changes in the characteristic conditions of individual ecosystems, because, unless man intervenes, the tree line on a mountain or the passage between grassland and savannah remains approximately static over a human lifetime.③ It is only on the millennial scale that such boundaries migrate significantly, or that characteristic regional ecosystems disappear. [CJ2] ④Urban sprawl, deforestation, overgrazing, and intensive agriculture are accomplishing in a few decades what nature cannily [剑3] do in centuries, but that sad fact does not alter the argument. ⑤[CJ4] Although the human population explosion can produce pressures that rapidly shift ecological boundaries and modify ecosystems ashore, it is paradoxically more difficult directly to modify the average locations of the ephemeral and shifting ecological boundaries of the sea. ⑥We can accomplish this only indirectly by atmospheric modification, resulting in a changed global climate and a shifted ocean circulation.[CJ5] 

①Indeed, if we are agreed that the regional characteristics of marine ecosystems are consequent on[CJ6]  the characteristics of the physical environment, then we must assume that ecological conditions are as impermanent as the physical conditions themselves. ②And these, it is now well understood, are in continual flux and state of change at all scales of variability.

ashore 岸上

①观点，水生系统没有陆地系统长久

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②事实

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③事实

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④观点

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⑤观点

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⑥观点

 [剑1]事实

 [CJ2]顺承陆地稳定，

 [剑3]精明地，机灵地，用心地

 [CJ4]让步，尽管人类活动可以快速改变陆地，可是不能改变海洋。

 [CJ5]人类无法直接影响海洋多变的生态边界，只能间接

 [CJ6]随之而来，跟随

1. The primary purpose of the passage is to 可以算一篇现象解释★★

A. examine differences in the threats faced by marine and terrestrial ecosystems. NE/无关，只有④⑤有

B. explain how human intervention has affected marine and terrestrial ecosystems. 无关，以偏概全

C. discuss a distinguishing feature of marine ecosystems

D. present a debate regarding the causes of marine ecosystem impermanence NE/无关，并不是讨论起因，仅仅是在说不同

E. discuss certain consequences of marine ecosystem impermanence 没有consequence的证据

2. The passage indicates which of the following about the “ecological boundaries of the sea?” 直接细节，直接定位 ☆

A. They have become increasingly sensitive to changes in global climate. 没有证据

B. They are not significantly impacted by changes in Earth’s atmosphere. 没有impact的证据

C. Their stability is essential to the health of marine ecosystems. 没有证据

D. They are more closely tied to surrounding physical conditions than are analogous boundaries on land 相反/没有证据？

E. They are less susceptible to direct human intervention than are analogous boundaries on land. 符合