gwd-13-34搜了一下没问过

Q34 to Q37:

      A small number of the forest

       species of lepidoptera (moths and

       butterflies, which exist as caterpillars

Line       during most of their life cycle) exhibit

  (5)       regularly recurring patterns of popu-

lation growth and decline—such

fluctuations in population are known

as population cycles.  Although many

different variables influence popula-

(10)      tion levels, a regular pattern such as

a population cycle seems to imply a

dominant, driving force.  Identification

of that driving force, however, has

proved surprisingly elusive despite

(15)      considerable research.  The com-

mon approach of studying causes of

population cycles by measuring the

mortality caused by different agents,

such as predatory birds or parasites,

(20)      has been unproductive in the case of

       lepidoptera.  Moreover, population

       ecologists’ attempts to alter cycles

by changing the caterpillars’ habitat

and by reducing caterpillar popula-

(25)      tions have not succeeded.  In short,

the evidence implies that these insect

populations, if not self-regulating, may

at least be regulated by an agent more

intimately connected with the insect than

(30)      are predatory birds or parasites.

      Recent work suggests that this

agent may be a virus.  For many

       years, viral disease had been

reported in declining populations

(35)     of caterpillars, but population ecolo-

gists had usually considered viral

disease to have contributed to the

decline once it was underway rather

than to have initiated it.  The recent

(40)     work has been made possible by

new techniques of molecular biology

that allow viral DNA to be detected

at low concentrations in the environ-

ment.  Nuclear polyhedrosis viruses

(45)      are hypothesized to be the driving

force behind population cycles in

lepidoptera in part because the

viruses themselves follow an infec-

tious cycle in which, if protected from

(50)      direct sun light, they may remain

virulent for many years in the envi-

ronment, embedded in durable

crystals of polyhedrin protein.

Once ingested by a caterpillar,

(55)      the crystals dissolve, releasing

the virus to infect the insect’s cells.

Late in the course of the infection,

millions of new virus particles are

formed and enclosed in polyhedrin

(60)      crystals.  These crystals reenter the

environment after the insect dies and

decomposes, thus becoming avail-

able to infect other caterpillars.

      One of the attractions of this

(65)      hypothesis is its broad applicability.

Remarkably, despite significant differ-

ences in habitat and behavior, many

species of lepidoptera have population

cycles of similar length, between eight

(70)      and eleven years.  Nuclear polyhe-

drosis viral infection is one factor these disparate species share.

34.which of the following, if true, would most weaken the author's conclusion in lines 25-30?

B. new experiments in which the habitats of lepidoptera are altered in previously untried ways resut in the shortening of lepidoptera population cycles.

C. recent experiments have revealed that the nuclear polyhedrosis virus is present in a number of predators and parasites of lepidoptera.

答案是B,可是我怎么看都觉得B与25-30的内容无关呀

我选的C,病毒出现在predators and parasites 身上,由此影响lepidoptera,不是正好削弱了吗?

up~

agree to have C.

B
        mentioned habitats
            of lepidoptera, which I think are pretty much intimately related the insects themselves. ==> B actually support the arguement.

我也认为是C

populations, if not self-regulating, may

at least be regulated by an agent more

intimately connected with the insect than

are predatory birds or parasites.

if not self-regulating:出题点，似乎也是G经常喜欢干的事情！

可是我怎么看都觉得B与25-30的内容无关呀：这就对啦，因为说的是self-regulating的事情呀！

还是不是很明白

C错误是不是因为那个nuclear polyhedrosis virus是后来实验的结论，和题目问的结论不沾边？

我顶，大家看看这道题，C明明是削弱，怎么回事加强呢？

从那点看出来B 讲的是self-regulating的事啊？