老托福阅读真题passage 11-智课教育旗下智课教育.pdfVIP

智 课 网 托 福 备 考 资 料 老托福阅读真题PASSAGE 11-智课教育旗下智课教育 本文和大家分享的是老托福阅读真题PASSAGE 11，练习真题是最 重要也最有效的复习方法，大家在复习托福阅读考试的时候一定要对真 题重视起来。 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