[求助]GWD-3-5

sissa

GWD-3-Q5 to GWD-3-Q7:

      In 1994, a team of scientists led

        by David Mckay began studying the

        meteorite ALH84001, which had been

Line  discovered in Antarctica in 1984.

  (5)        Two years later, the McKay team

announced that ALH84001, which

scientists generally agree originated

on Mars, contained compelling evi-

dence that life once existed on Mars.

(10)        This evidence includes the discovery

of organic molecules in ALH84001,

the first ever found in Martian rock.

Organic molecules—complex, carbon-

based compounds—form the basis for

(15)        terrestrial life.  The organic molecules

found in ALH84001 are polycyclic aro-

matic hydrocarbons, or PAH’s.  When

microbes die, their organic material

often decays into PAH’s.

(20)              Skepticism about the McKay team’s

        claim remains, however.  For example,

        ALH84001 has been on earth for

13,000 years, suggesting to some

scientists that its PAH’s might have

(25)        resulted form terrestrial contamination.

However, McKay’s team has demon-

strated that the concentration of PAH’s

increases as one looks deeper into

ALH84001, contrary to what one would

(30)        expect from terrestrial contamination.

The skeptic’s strongest argument,

however, is that processes unrelated

        to organic life can easily produce all

the evidence found by McKay’ steam,

including PAH’s.  For example, star

formation produces PAH’s.  Moreover,

PAH’s frequently appear in other

meteorites, and no one attributes

       their presence to life processes.

(40)       Yet McKay’s team notes that the

particular combination of PAH’s

in ALH84001 is more similar to the

combinations produced by decaying

organisms than to those originating

form nonbiological processes.

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GWD-3-Q5:      

The passage asserts which of the following about the claim that ALH84001 originated on Mars?

A.      It was initially proposed by the McKay team of scientists.

B.      It is not a matter of widespread scientific dispute.

C.      It has been questioned by some skeptics of the McKay team’s work.

D.     It has been undermined by recent work on PAH’s.

E.      It is incompatible with the face that ALH84001 has been on Earth for 13,000 years.

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請問答案為什麼是B

而不是C呢~

謝謝解答~!!

wangyu73cn

简单来说，即文中就没有怀疑ALH84001 来源于Mars这一判断。

请别人也看看吧

[此贴子已经被作者于2005-1-17 13:14:18编辑过]

xealot

Agree with Wangyu's point.

Just kind of curious why you think C is right...?

weiqifang

第二十行第一句话：Skepticism about the McKay team's claim remains, however.  不是说明有人怀疑吗？

给一个选A的理由好吗？ 整篇文章不是在说有争议吗？

swlfx

怀疑者质疑的是PAH’s的来源问题，而不是ALH84001的来源问题。

swlfx

对于ALH84001的来源，基本是个被普遍认可的问题。见which  scientists generally agree originated  on Mars,

amy9301

明白了，谢谢