gwd6-5-7

Q5 to Q7:

      According to a theory advanced

       by researcher Paul Martin, the wave

       of species extinctions that occurred

Line       in North America about 11,000 years

  (5)       ago, at the end of the Pleistocene era,

can be directly attributed to the arrival

of humans, i.e., the Paleoindians, who

were ancestors of modern Native

Americans.  However, anthropologist

(10)      Shepard Krech points out that large

animal species vanished even in areas

where there is no evidence to demon-

strate that Paleoindians hunted them.

Nor were extinctions confined to large

(15)      animals:  small animals, plants, and

insects disappeared, presumably not

all through human consumption.  Krech

also contradicts Martin’s exclusion of

climatic change as an explanation by

(20)      asserting that widespread climatic

       change did indeed occur at the end of

       the Pleistocene.  Still, Krech attributes

secondary if not primary responsibility

for the extinctions to the Paleoindians,

(25)      arguing that humans have produced

local extinctions elsewhere.  But,

according to historian Richard White,

even the attribution of secondary

responsibility may not be supported

(30)      by the evidence.  White observes that

Martin’s thesis depends on coinciding

dates for the arrival of humans and the

       decline of large animal species, and

Krech, though aware that the dates

(35)      are controversial, does not challenge

them; yet recent archaeological

discoveries are providing evidence

that the date of human arrival was

much earlier than 11,000 years ago.

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Q7:

In the last sentence of the passage, the author refers to “recent archaeological discoveries” (lines 36-37) most probably in order to

refute White’s suggestion that neither Maritn nor Krech adequately account for Paleoindians’ contributions to the Pleistocene extinctions

cast doubt on the possibility that a more definitive theory regarding the causes of the Pleistocene extinctions may be forthcoming

suggest that Martin’s, Krech’s, and White’s theories regarding the Pleistocene extinctions are all open to question

call attention to the most controversial aspect of all the current theories regarding the Pleistocene extinctions

provide support for White’s questioning of both Martin’s and Krech’s positions regarding the role of Paleoindians in the Pleistocene extinctions

              according to historian Richard White,

even the attribution of secondary

responsibility may not be supported

(30)      by the evidence.  

我理解这段话的意思是不是说：w认为即使认为那些古代人在生物灭绝中期的作用第二重要的观点也是没有根据的。

言下之意是说人类在物种灭绝中期的作用是微不足道的。

而后来发现的证据却发现人类比原来推测的时间要早很多来到那里，也就是又可能队伍中的灭绝又责任，这个观点与w的正好是反的。

答案为什么是e呢？

the wave of species extinctions that occurred in North America about 11,000 years ago.

中的the wave of species extinctions 什么意思呀,这个wave没见过. 金山词霸查了, 朗文下载安装有问题,郁闷.

According to LDOCE,

wave:

3
▶EOPLE AND THINGS◀
[countable] a sudden increase in the number of people or things arriving at the same time
wave of
a new wave of immigrants They faced wave after wave of fresh troops.