请教XDF补充材料上的PASSAGE20！！

Species interdependence in nature confers many

benefits on the species involved, but it can also become a

point of weakness when one species involved in the rela-

tionship is affected by a catastrophe. Thus, flowering

(5) plant species dependent on insect pollination, as opposed

to self-pollination or wind pollination, could be endan-

gered when the population of insect-pollinators is depleted

by the use of pesticides.

   In the forests of New Brunswick, for example,

(10)
                various pesticides have been sprayed in the past 25 years

in efforts to control the spruce budworm, an economi-

cally significant pest. Scientists have now investigated

the effects of the spraying of Matacil, one of the anti-

budworm agents that is least toxic to insect-pollinators.

(15)
                They studied Matacil’s effects on insect mortality in a

wide variety of wild insect species and on plant fecun-

dity, expressed as the percentage of the total flowers on

an individual plant that actually developed fruit and

bore seeds. They found that the most pronounced

(20)
                mortality after the spraying of Matacil occurred among

the smaller bees and one family of flies, insects that were

all important pollinators of numerous species of plants

growing beneath the tree canopy of forests. The fecun-

dity of plants in one common indigenous species, the

(25)
                red-osier dogwood, was significantly reduced in the

sprayed areas as compared to that of plants in control

plots where Matacil was not sprayed. This species is

highly dependent on the insect-pollinators most vulner-

able to Matacil. The creeping dogwood, a species similar

(30) to the red-osier dogwood, but which is pollinated by

large bees, such as bumblebees, showed no significant

decline in fecundity. Since large bees are not affected by

the spraying of Matacil. these results and weight to the

argument that spraying where the pollinators are sensi-

(35)
                tive to the pesticide used decreases plant fecundity.

     The question of whether the decrease in plant fecun-

dity caused by the spraying of pesticides actually causes

a decline in the overall population of flowering plant

species still remains unanswered. Plant species dependent

(40)
                solely on seeds for survival or dispersal are obviously

more vulnerable to any decrease in plant fecundity that

occurs, whatever its cause. If, on the other hand, vegeta-

tive growth and dispersal (by means of shoots or runners)

are available as alternative reproductive strategies for a

(45)
                species, then decreases in plant fecundity may be of little

consequence. The fecundity effects described here are

likely to have the most profound impact on plant species

with all four of the following characteristics: a short life

span, a narrow geographic range, an incapacity for vege-

(50)
            tative propagation, and a dependence on a small number

of insect-pollinator species. Perhaps we should give special

attention to the conservation of such plant species since

they lack key factors in their defenses against the envi-

ronmental disruption caused by pesticide use.

5. It can be inferred that which of the following is true of

  plant fecundity as it is defined in the passage?

  (A) A plant’s fecundity decreases as the percentage of

     unpollinated flowers on the plant increases

  (B) A plant’s fecundity decreases as the number of

     flowers produced by the plant decreases.

  (C) A plant’s fecundity increases as the number of

     flowers produced by the plant increases.

  (D) A plant’s fecundity is usually low if the plant relies

     on a small number of insect species for pollination.

  (E) A plant’s fecundity is high if the plant can reproduce

     quickly by means of vegetative growth as well as by

     the production of seeds.

6. It can be inferred from the passage that which of the

  following plant species would be LEAST likely to

  experience a decrease in fecundity as a result of the

  spraying of a pesticide not directly toxic to plants?

  (A) A flowering tree pollinated by only a few insect

     species

  (B) A kind of insect-pollinated vine producing few

     flowers

  (C) A wind-pollinated flowering tree that is short-lived

  (D) A flowering shrub pollinated by a large number of

     insect species

  (E) A type of wildflower typically pollinated by larger

     insects

第五题选A的依据是哪里呢？

第六题答案是C,我觉得C不对啊。short-lived 不就等于 short life span，这一特点是很受fecunity 影响的阿。相比之下我觉得应该是D. a large number of insect species。

can anyone help?

同意梦不落

我也觉得第六题应该是D

第五题选A是因为第一段说：依靠昆虫播种的植物，

当昆虫被杀虫剂感染时-->无法播种(导致unpollinated flower)-->植物也面临危险

请指教。

6. It can be inferred from the passage that which of the

  following plant species would be LEAST likely to

  experience a decrease in fecundity as a result of the

  spraying of a pesticide not directly toxic to plants?

  (A) A flowering tree pollinated by only a few insect

     species

  (B) A kind of insect-pollinated vine producing few

     flowers

  (C) A wind-pollinated flowering tree that is short-lived

  (D) A flowering shrub pollinated by a large number of

     insect species

  (E) A type of wildflower typically pollinated by larger

If, on the other hand, vegeta-

tive growth and dispersal (by means of shoots or runners)

are available as alternative reproductive strategies for a

(45)
                        species, then decreases in plant fecundity may be of little

consequence.

5------They studied Matacil’s effects on insect mortality in a

wide variety of wild insect species and on plant fecun-

dity, expressed as the percentage of the total flowers on

an individual plant that actually developed fruit and

bore seeds.

wide variety of wild insect species and on plant fecun-

dity, expressed as the percentage of the total flowers on

an individual plant that actually developed fruit and

bore seeds.

第六题应该是C的,人家问的是least而且wind-pollinated根本就和文中的小列举无关,short-lived也就没有作用了,这就是ETS故意的陷阱,让我们以为那个a large number of insect species可以和文中的a small number of insect species相抵触,但仔细分析发现两种描述的根基是一样的,虽然想对数量不同!