托福閱讀輔導(dǎo):老托福閱讀真題及答案passage11
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老托福閱讀文本 passage11
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.
老托福閱讀題目 passage11
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.
老托福閱讀答案 passage11
正確答案： CAABD CADD
托福閱讀技巧：詞匯題應(yīng)對(duì)方法
為什么很多考生會(huì)對(duì)詞匯題束手無(wú)措?一方面是因?yàn)榭忌脑~匯量達(dá)不到，OG中詞匯題的解釋里有一句話，there is no “l(fā)ist of words” that must be tested. 這句話就告訴考生死了那條心去背所謂的大綱詞匯，因?yàn)闆](méi)有大綱，而考試中要考查到的單詞可能是來(lái)自牛津字典或朗文字典中的任何一個(gè)單詞，范圍大的離譜;而另一方面則是因?yàn)橛械目忌鷽](méi)有學(xué)會(huì)從上下文或者從語(yǔ)法結(jié)構(gòu)去猜測(cè)詞義。
因?yàn)镺G中的解釋還有一句a word might have more than one meaning, but in the reading passage, only one of those meaning is relevant. 所以很有可能考生在考試中所碰到的詞匯并不是已經(jīng)讓人熟知的第一詞義，而是要根據(jù)語(yǔ)境上下文推斷出的第二詞義甚至是第三詞義，所以又對(duì)考生做題增加了難度。最可悲的是不僅文章中的單詞意思不知道，連4個(gè)選項(xiàng)中的單詞都有不認(rèn)識(shí)不熟悉的，這樣的結(jié)果就只能是亂猜一氣，聽(tīng)天由命全憑運(yùn)氣，當(dāng)然考試結(jié)果也不會(huì)好。所以在此將給考生一點(diǎn)準(zhǔn)備新托福閱讀考試詞匯題的建議和解題方法，希望能給考生攻克詞匯題給予一些幫助。
Tip: 單詞記憶
單詞記憶主要就是背單詞。背單詞是很多同學(xué)覺(jué)得非常痛苦的事情，經(jīng)常會(huì)有學(xué)生來(lái)問(wèn)藥怎么背，背了一些又馬上忘了另外一些。所以關(guān)于如何去背單詞，在這里有幾點(diǎn)建議：
1、利用零散的時(shí)間背單詞。利用零散的時(shí)間背單詞可以使用單詞卡片。不過(guò)，為了保證效率，首先要確定哪些單詞需要記憶。理論上，單詞量越多越好。實(shí)際上，如果一味貪多，結(jié)果容易打疲勞戰(zhàn)，而且效率低。所以，只記那些?？嫉暮诵脑~匯，而對(duì)于那些不太常用的學(xué)科名詞、物質(zhì)名詞一般加以忽略。
2、進(jìn)行高頻率的重復(fù)，建議把重復(fù)的周期控制在7天以?xún)?nèi)。具體說(shuō)來(lái)，就是每天背100個(gè)單詞，將過(guò)一遍這些單詞的時(shí)間控制在半個(gè)小時(shí)以?xún)?nèi)，每天過(guò)4遍，第二天再過(guò)一遍前一天的。如果程度不是很好的同學(xué)可以壓縮到50個(gè)左右，但盡量不要低于50個(gè)。單詞材料可以找一些相關(guān)的新托福閱讀詞匯書(shū)，或者是以往考過(guò)的詞匯題內(nèi)容。
把背單詞和閱讀相結(jié)合。廣泛的閱讀也是增加詞匯量的一種方法，并且能夠在閱讀中加強(qiáng)對(duì)已經(jīng)背過(guò)的單詞的記憶。當(dāng)一篇文章的生詞量在5%左右的時(shí)候，這些生詞的詞義是可推的。所以我們?cè)谶x擇閱讀材料的時(shí)候，應(yīng)盡量將單詞量控制在10%左右。單詞太多，看不懂文章，太少又起不到提高的作用。相關(guān)材料可以上一些網(wǎng)站看，例如economist, national geographic等等。
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