託福閱讀對27個多少分

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託福閱讀對27個多少分

關於託福閱讀錯幾個得多少分的問題，大家可以參考託福閱讀計分方法：

1、託福三篇文章(如遇加試時從五篇中隨機選三篇)計分，每篇12-14道題。

2、三篇文章回答正確的題目數量加起來就能得出託福閱讀總分。

3、除重要歸類題和觀點題以外，每道題的分值都是1分。

4、重要觀點題的分值可能是2分。歸類題爲3或4分。

5、考試所得分數範圍：0-30分。

託福閱讀TPO34原文第3篇:昆蟲保護植物

託福閱讀原文

Protection of Plants by Insects

【1】Many plants - one or more species of at least 68 different families -can secrete nectar even when they have no blossoms, because they bearextrafloral nectaries (structures that produce nectar) on stems, leaves, leafstems, or other e plants usually occur where ants are abundant,most in the tropics but some in temperate areas. Among those of northeasternNorth America are various plums, cherries, roses, hawthorns, poplars, and floral nectar, extrafloral nectar consists mainly of water with a highcontent of dissolved sugars and, in some plants, small amounts of amino extrafloral nectaries of some plants are known to attract ants and otherinsects, but the evolutionary history of most plants with these nectaries isunknown. Nevertheless, most ecologists believe that all extrafloral nectariesattract insects that will defend the plant.

【2】Ants are portably the most frequent and certainly the most persistentdefenders of plants. Since the highly active worker ants require a great deal ofenergy, plants exploit this need by providing extrafloral nectar that suppliesants with abundant energy. To return this favor, ants guard the nectaries,driving away or killing intruding insects that might compete with ants fornectar. Many of these intruders are herbivorous and would eat the leaves of theplants.

【3】Biologists once thought that secretion of extrafloral nectar has somepurely internal physiological function, and that ants provide no benefitwhatsoever to the plants that secrete it. This view and the opposing“protectionist” hypothesis that ants defend plants had been disputed for over ahundred years when, in 1910, a skeptical William Morton Wheeler commented on thecontroversy. He called for proof of the protectionist view: that visitations ofthe ants confer protection on the plants and that in the absence of the insectsa much greater number would perish or fail to produce flowers or seeds than whenthe insects are present. That we now have an abundance of the proof that wascalled for was established when Barbara Bentley reviewed the relevant evidencein 1977, and since then many more observations and experiments have providedstill further proof that ants benefit plants.

【4】One example shows how ants attracted to extrafloral nectaries protectmorning glories against attacking insects. The principal insect enemies of theNorth American morning glory feed mainly on its flowers or fruits rather thanits leaves. Grasshoppers feeding on flowers indirectly block pollination and theproduction of seeds by destroying the corolla or the stigma, which receives thepollen grains and on which the pollen germinates. Without their colorfulcorolla, flowers do not attract pollinators and are not fertilized. An adultgrasshopper can consume a large corolla, about 2.5 inches long, in an rpillars and seed beetles affect seed production directly. Caterpillarsdevour the ovaries, where the seeds are produced, and seed beetle larvae eatseeds as they burrow in developing fruits.

【5】Extrafloral nectaries at the base of each sepal attract several kinds ofinsects, but 96 percent of them are ants, several different species of buds are still small, less than a quarter of an inch long, the sepalnectaries are already present and producing nectar. They continue to do so asthe flower develops and while the fruit matures. Observations leave little doubtthat ants protect morning glory flowers and fruits from the combined enemy forceof grasshoppers, caterpillars, and seed beetles. Bentley compares the seedproduction of six plants that grew where there were no ants with that ofseventeen plants that were occupied by ants. Unprotected plants bore only 45seeds per plant, but plants occupied by ants bore 211 seeds per plant. Althoughants are not big enough to kill or seriously injure grasshoppers, they drivethem away by nipping at their feet. Seed beetles are more vulnerable becausethey are much smaller than grasshoppers. The ants prey on the adult beetles,disturb females asthey lay their eggs on developing fruits, and eat many of theeggs they do manage to lay

託福閱讀TPO34試題第3篇:昆蟲保護植物

rding to paragraph 1，floral nectar and extrafloral nectar are alikein that

are likely to be produced by the same plants.

basically consist of the same chemical components.

attract only insects that will defend the plant.

are produced by the same parts of the plant.

say that ants are "persistent" defenders of plants means that

defend plants against a wide variety of threats.

continue to defend plants for as long as the plants arethreatened.

are successful defenders of plants.

are easily observable defenders of plants.

can be inferred from paragraph 2 about the ants that are attractedto the extrafloral nectaries?

do not eat the leaves of the plants that produce extrafloralnectar.

live almost entirely on extrafloral nectar.

spend most of their energy guarding extrafloral nectaries.

frequently fight among themselves over extrafloral nectar.

rding to paragraph 3, what was the position of the opponents of the"protectionist" hypothesis?

afloral nectar provides plants with a direct defense against attackby insects.

substantially benefit plants that secrete extrafloral nectar.

secretion of extrafloral nectar plays a role in the plant’s internalfunctioning.

visit plants that secrete extrafloral nectar as often as they visitplants that do not.

word "skeptical" in the passage is closest in meaning to

ous.

tful.

-minded.

tical.

h of the sentences below best expresses the essential information jnthe highlighted sentence in the passage Incorrect choices change the meaning inimportant ways or leave out essential information.

now have ample proof that ants benefit plants.

ara Bentley has called for additional proof that ants benefitplants.

1977 Barbara Bentley conducted research that proved that all priorstudies were wrong.

f that ants benefit plants will require many more observations andexperiments.

rding to paragraph 4, what effect does the destruction of the corollahave on plants.

leaves the seeds exposed and unprotected.

prevents the stigma from developing.

keeps pollen grains from attaching properly.

prevents the flower from attracting pollinators.

word "devour" in the passage is closest in meaning to

ck.

.

ge.

er.

role does paragraph 5 play in the passage?

offers various kinds of evidence for the protectionist view.

presents the study that first proved that ants benefit plants.

explains how insects find sources of nectar.

presents information that partly contradicts the protectionistview.

word "vulnerable" in the passage is closest in meaning to

rous.

ful.

to attack.

icult to locate.

rding to paragraph 5, what did Bentley’s comparative study show?

more plants grew in places where ants were present than where theywere absent.

ants preferred plants with low seed production to plants with highseed production.

plants occupied by ants produced many more seeds than those that werenot occupied by ants.

plants that grew in places without ants were much smaller and weakerthan those that grew in places where ants were present.

rding to paragraph 5, ants defend morning glory plants from seedbeetles in each of the following ways EXCEPT:

ing adult beetles off the plants by nipping at their feet.

hing and eating adult beetles.

ng beetle eggs they find on developing fruits.

ng it difficult for beetles to lay eggs on developing fruits.

13. Look at the four squares [■] that indicate where the following sentencecould be added to the passage. Where would the sentence best fit? Sometimes theycapture the insects to feed their protein-hungry larvae.

Ants are portably the most frequent and certainly the most persistentdefenders of plants. ■【A】 Since the highly active worker ants require a greatdeal of energy, plants exploit this need by providing extrafloral nectar thatsupplies ants with abundant energy. ■【B】 To return this favor, ants guard thenectaries, driving away or killing intruding insects that might compete withants for nectar. ■【C】 Many of these intruders are herbivorous and would eat theleaves of the plants. ■【D】

14. Directions: An introductory sentence for a brief summary of the passageof the passage is provided below. Complete the summary by selecting the THREEanswer choices that express the most important ideas in the passage. Some answerchoices do not belong in the summary because they express ideas that are notpresented in the passage or are minor ideas in the passage. This questions isworth 2 points.

Many plants have extrafloral nectaries that produce nectar even duringperiods in which the plant is not flowering.

utionary history shows that plants that produce extrafloral nectaroriginated in the tropics.

afloral nectar has a higher concentration of sugar than floral nectarand is more attractive to ants and other insects.

protectionist hypothesis is that extrafloral nextar attracts ants,and that the ants, in order to preserve this energy-rich food source, attackinsects that might harm the plant.

ence accumulated during the twentieth century proved that antsprovide significant benefits for plants with extrafloral nectaries.

arch has shown that American morning glory plants that are protectedby ants produce significantly more seeds than morning glory plants that are notprotected by ants.

generally ignore small insects, but they will eat the adults oflarge insect species as well as their eggs and larvae.

託福閱讀TPO34第3篇:昆蟲保護植物參考答案

1.B

2.B

3.A

4.D

5.A

6.A

7.C

8.B

9.B

10.C

11.C

12.A

13.C