想要提升托福閱讀的做題速度，我們就要學(xué)會(huì)在文章中找到定位詞，能夠快速找到定位詞，我們才能在有限的時(shí)間內(nèi)又快又對(duì)地做完閱讀題目。那么，什么是閱讀定位詞?做閱讀過(guò)程中應(yīng)該如何快速定位托福閱讀定位詞?小編來(lái)給大家詳細(xì)解答下。

托福閱讀速度提升方法：學(xué)會(huì)找定位詞!

一.什么是托福閱讀定位詞?

其實(shí)很簡(jiǎn)單，打個(gè)比方，你和朋友約好了去酒吧，朋友和你說(shuō)酒吧在沈陽(yáng)新東方正對(duì)面，這個(gè)酒吧你是不知道地點(diǎn)的，也就是你的目的地;而新東方卻很熟知，那么你只需找到新東方便可以找到酒吧了。在這里新東方是已知的，就是用來(lái)定位的詞匯，而酒吧則是你的目的所在，也便是你要找的答案。

定位詞的稱呼有很多，如關(guān)鍵詞，主旨詞，功能詞，中心詞等等。這些只是個(gè)名稱罷了，含義都是一致的：一個(gè)可以根據(jù)題干回原文定位，并能夠找到出處的詞，這個(gè)題干中的詞就是定位詞or key word。

二.定位詞具體特征分析

定位詞總體特征：不可變性和細(xì)節(jié)性

不可變性：定位詞是用來(lái)定位的，所以必須找那些回原文依然不變的詞匯，才有意義。通常不用動(dòng)詞和副詞來(lái)定位。通常是名詞或充當(dāng)定語(yǔ)的形容詞。

細(xì)節(jié)性：不要找大概念的詞匯，更不要拿代表全文主旨的詞匯來(lái)定位。換句話說(shuō)不要找那些原文一大堆的詞匯，無(wú)法定位。

如，95年英國(guó)劍橋委員會(huì)British Council給出的唯一樣題文章的題目是:The Spectacular Eruption of Mount St.Helens

下面有一道選擇題是“According to the text the eruption of Mount St.Helens and other volcanoes has influenced our climate by…”

拿這道題為例，如果大家把Mount St.Helens作為關(guān)鍵詞回原文進(jìn)行定位，那你會(huì)郁悶致死，全文主要講的就是圣海倫斯火山的噴發(fā)，原文有N多個(gè)Mount St.Helens，所以即使這個(gè)詞屬于大寫的專有名詞，但他違背了細(xì)節(jié)性，是概括性的詞匯，也不能作為定位詞來(lái)尋找答案。

究竟哪些詞在托福閱讀當(dāng)中充當(dāng)定位詞?

三.托福閱讀中的定位詞都有哪些類別?

1.特殊詞匯

在閱讀中有一些詞張的比較特殊，這種詞很容易被記住，也很容易回原文定位。

好比，在大街上上看到一個(gè)人光著身子跑步-------特殊難看

一個(gè)人的個(gè)子超高，像姚明一樣------特殊長(zhǎng)

一個(gè)人身上穿著10多種顏色的衣服，而且不停的搖頭-----特殊怪

特殊怪，特殊長(zhǎng)，特殊難

這三種詞就是特殊詞的所有特征，在文中看到這樣的詞，一定要警惕。如，

Sequoia美洲杉---特殊怪，很好定位，也經(jīng)常作為考點(diǎn)。

sodium【化學(xué)】鈉---特殊難，大家只要知道是一種化學(xué)元素足矣。

Simultaneous同時(shí)的---特殊長(zhǎng)，這種詞本身的特點(diǎn)決定應(yīng)作為定位詞。

2.數(shù)字：通常指時(shí)間，金錢和百分比。

有一個(gè)道題目是這樣問(wèn)的：

“What are the dates of the TWO major eruptions before 1980?”

那么像1980 3185$ 69%這些詞因?yàn)殚L(zhǎng)相原因，段落全是英文，突然跑出來(lái)幾個(gè)數(shù)字，十分顯眼，也就很好回原文找到他們。

3.專有名詞：

斜體字，大寫人名,地名，大寫的專有名詞，這一點(diǎn)大家都很熟悉，不用多說(shuō)。

4.特殊符號(hào)：

在特殊符號(hào)里或者旁邊的詞，最好通過(guò)符號(hào)回原文進(jìn)行定位，如“paper conversation”，(three cubic miles)這些詞本身并沒(méi)有什么特別，但放在符號(hào)里面，就可以根據(jù)符號(hào)回原文進(jìn)行尋找。

托福閱讀真題1

Plants are subject to attack and infection by a remarkable variety of symbiotic species and have evolved a diverse array of mechanisms designed to frustrate the potential colonists. These can be divided into preformed or passive defense mechanisms and inducible or active systems. Passive plant defense comprises physical and chemical barriers that prevent entry of pathogens, such as bacteria, or render tissues unpalatable or toxic to the invader. The external surfaces of plants, in addition to being covered by an epidermis and a waxy cuticle, often carry spiky hairs known as trichomes, which either prevent feeding by insects or may even puncture and kill insect larvae. Other trichomes are sticky and glandular and effectively trap and immobilize insects.

If the physical barriers of the plant are breached, then preformed chemicals may inhibit or kill the intruder, and plant tissues contain a diverse array of toxic or potentially toxic substances, such as resins, tannins, glycosides, and alkaloids, many of which are highly effective deterrents to insects that feed on plants. The success of the Colorado beetle in infesting potatoes, for example, seems to be correlated with its high tolerance to alkaloids that normally repel potential pests. Other possible chemical defenses, while not directly toxic to the parasite, may inhibit some essential step in the establishment of a parasitic relationship. For example, glycoproteins in plant cell walls may inactivate enzymes that degrade cell walls. These enzymes are often produced by bacteria and fungi.

Active plant defense mechanisms are comparable to the immune system of vertebrate animals, although the cellular and molecular bases are fundamentally different. Both, however, are triggered in reaction to intrusion, implying that the host has some means of recognizing the presence of a foreign organism. The most dramatic example of an inducible plant defense reaction is the hypersensitive response. In the hypersensitive response, cells undergo rapid necrosis — that is, they become diseased and die — after being penetrated by a parasite; the parasite itself subsequently ceases to grow and is therefore restricted to one or a few cells around the entry site. Several theories have been put forward to explain the basis of hypersensitive resistance.

1. What does the passage mainly discuss?

(A) The success of parasites in resisting plant defense mechanisms

(B) Theories on active plant defense mechanisms

(C) How plant defense mechanisms function

(D) How the immune system of animals and the defense mechanisms of plants differ

2. The phrase subject to in line 1 is closest in meaning to

(A) susceptible to

(B) classified by

(C) attractive to

(D) strengthened by

3. The word puncture in line 8 is closest in meaning to

(A) pierce

(B) pinch

(C) surround

(D) cover .

4. The word which in line 12 refers to

(A) tissues

(B) substances

(C) barriers

(D) insects

5. Which of the following substances does the author mention as NOT necessarily being toxic to

the Colorado beetle?

(A) resins

(B) tannins

(C) glycosides

(D) alkaloids

6. Why does the author mention glycoproteins in line 17?

(A) to compare plant defense mechanisms to the immune system of animals

(B) to introduce the discussion of active defense mechanisms in plants

(C) to illustrate how chemicals function in plant defense

(D) to emphasize the importance of physical barriers in plant defense

7. The word dramatic in line 23 could best be replaced by

(A) striking

(B) accurate

(C) consistent

(D) appealing

8. Where in the passage does the author describe an active plant-defense reaction?

(A) Lines 1-3

(B) Lines 4-6

(C) Lines 13-15

(D) Lines 24-27

9. The passage most probably continues with a discussion of theories on

(A) the basis of passive plant defense

(B) how chemicals inhibit a parasitic relationship.

(C) how plants produce toxic chemicals

(D) the principles of the hypersensitive response.

托福閱讀真題2

Among the species of seabirds that use the windswept cliffs of the Atlantic coast of Canada in the summer to mate, lay eggs, and rear their young are common murres, Atlantic puffins, black-legged kittiwakes, and northern gannets. Of all the birds on these cliffs, the black-legged kittiwake gull is the best suited for nesting on narrow ledges. Although its nesting habits are similar to those of gulls that nest on flat ground, there are a number of important differences related to the cliff-nesting habit.

The advantage of nesting on cliffs is the immunity it gives from foxes, which cannot scale the sheer rocks, and from ravens and other species of gulls, which have difficulty in landing on narrow ledges to steal eggs. This immunity has been followed by a relaxation of the defenses, and kittiwakes do not react to predators nearly as fiercely as do ground-nesting gulls. A colony of Bonaparte's gulls responds to the appearance of a predatory herring gull by flying up as a group with a clamor of alarm calls, followed by concerted mobbing, but kittiwakes simply ignore herring gulls, since they pose little threat to nests on cliffs. Neither do kittiwakes attempt to conceal their nest. Most gulls keep the nest area clear of droppings, and remove empty eggshells after the chicks have hatched, so that the location of the nest is not given away. Kittiwakes defecate over the edge of the nest, which keeps it clean, but this practice, as well as their tendency to leave the nest littered with eggshells, makes its location very conspicuous.

On the other hand, nesting on a narrow ledge has its own peculiar problems, and kittiwake behavior has become adapted to overcome them. The female kittiwake sits when mating, whereas other gulls stand, so the pair will not overbalance and fall off the ledge. The nest is a deep cup, made of mud or seaweed, to hold the eggs safely, compared with the shallow scrape of other gulls, and the chicks are remarkably immobile until fully grown. They do not run from their nests when approached, and if they should come near to the cliff edge, they instinctively turn back.

1. What aspect of the kittiwake gull does the passage mainly discuss?

(A) Its defensive behavior

(B) It interactions with other gull species

(C) Its nesting habits

(D) Its physical difference from other gull species

2. The word rear in line 2 is closest in meaning to

(A) visit

(B) watch

(C) reverse

(D) raise

3. The word scale in line 8 is closest in meaning to

(A) climb

(B) avoid

(C) approach

(D) measure

4. The word immunity in line 9 is closest in meaning to

(A) distance

(B) transition

(C) protection

(D) reminder

5. Why is it difficult for ravens to steal the kittiwakes' eggs?

(A) The kittiwakes can see the ravens approaching the nest.

(B) The ravens cannot land on the narrow ledges where kittiwakes nest.

(C) The kittiwakes' eggs are too big for the ravens to carry.

(D) The female kittiwakes rarely leave the nest.

6. The author mentions that eggshells litter around the nests of kittiwakes in order to

(A) demonstrate that kittiwakes are not concerned about predators

(B) prove how busy kittiwakes are in caring for their offspring

(C) show a similarity to other types of gulls

(D) illustrate kittiwakes' lack of concern for their chicks

7. According to the passage , it can be inferred that which of the following birds conceal their

nest?

(A) Bonaparte's gulls

(B) Atlantic puffins

(C) Kittiwake gulls

(D) Northern gannets

8. The word it in line 17 refers to

(A) location

(B) edge

(C) nest

(D) practice

9. The word conspicuous in line 18 is closest in meaning to

(A) disordered

(B) suspicious

(C) noticeable

(D) appealing

10. The phrase On the other hand in line 19 is closest in meaning to

(A) therefore

(B) however

(C) for example

(D) by no means

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