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文章講解：

①M(fèi)arine ecosystems certainly have less permanence than terrestrial ecosystems.[劍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?[劍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觀點(diǎn)，水生系統(tǒng)沒有陸地系統(tǒng)長(zhǎng)久

↓

②事實(shí)

↓

③事實(shí)

↓

④觀點(diǎn)

↓

⑤觀點(diǎn)

↓

⑥觀點(diǎn)

?[劍1]事實(shí)

?[CJ2]順承陸地穩(wěn)定，

?[劍3]精明地，機(jī)靈地，用心地

?[CJ4]讓步，盡管人類活動(dòng)可以快速改變陸地，可是不能改變海洋。

?[CJ5]人類無法直接影響海洋多變的生態(tài)邊界，只能間接

?[CJ6]隨之而來，跟隨

1.?The primary purpose of the passage is to 可以算一篇現(xiàn)象解釋★★

A. examine?differences?in the threats faced by marine and terrestrial ecosystems. NE/無關(guān)，只有④⑤有

B. explain how human intervention has affected marine and terrestrial ecosystems.?無關(guān)，以偏概全

C. discuss a distinguishing feature of marine ecosystems

D. present a?debate?regarding the?causes?of marine ecosystem impermanence NE/無關(guān)，并不是討論起因，僅僅是在說不同

E. discuss certain?consequences?of marine ecosystem impermanence 沒有consequence的證據(jù)

?

2. The passage indicates which of the following about the “ecological boundaries of the sea?” 直接細(xì)節(jié)，直接定位 ☆

A. They have become?increasingly?sensitive?to changes in?global climate. 沒有證據(jù)

B. They are not significantly impacted by changes in Earth’s atmosphere.?沒有impact的證據(jù)

C. Their stability is essential to the health of marine ecosystems.?沒有證據(jù)

D. They are more closely tied to surrounding physical conditions than are analogous boundaries on land?相反/沒有證據(jù)？

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