托福阅读的思维方式就是托福阅读的出题方式，只有掌握了这种思维方式，才有可能在做题之前，预测到新托福阅读题的出题形式和特点，为找答案节省时间。老托福阅读试题的核心价值，在于其最贴近真题的阅读思维方式。此外老托福阅读真题比新托福IBT阅读文章要短，比较容易适应。这也是大家在备考托福的时候非常重要的一点。因为前期的入手如果能从容易的开始，就会形成一个循序渐进的过程方式，让大家的练习有一个提高的过程。
既然老托福阅读试题有这样的效果，那我们如何利用那有限的真题来达到锻炼自己的目的呢？事实上这就一个办法，就是坚持。本期为大家推荐老托福阅读的真题PASSAGE 11，附有原文及答案，希望对托福考生备考有所帮助。
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
正确答案： CAABD CADD
以上就是百利天下考试为大家整理的老托福阅读真题，考生可进行参考训练以提高自己的考试水平。若您想了解托福考试更多相关信息请关注百利天下出国考试。
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