托福閱讀真題文檔免費下載【答案 解析 譯文】.docx

智課網(wǎng)TOEFL備考資料托福閱讀真題文檔免費下載【答案+解析+譯文】 摘要： 托福閱讀真題文檔共有30套，應(yīng)有盡有，全部來源托福閱讀題庫，80%的學(xué)生因為擁有小馬版的托福閱讀真題文檔而成功考得理想成績，你還等什么？該出手時就出手，趕快點擊下載吧！ 托福 閱讀真題文檔里面包含有名師解析和翻譯文檔，完整版是由 小馬 的 托福閱讀 專家團(tuán)隊精心撰寫，12年來幫助90萬的學(xué)生成功拿到滿意offer，是廣大學(xué)生必不可少的閱讀備考資料，下面我們就來了解下托福閱讀真題文檔【答案+解析+譯文】的部分內(nèi)容。 托福閱讀真題文檔免費下載【答案+解析+譯文】passage1 Symbiotic Relationships A symbiotic relationship is an interaction between two or more species in which one species lives in or on another species. There are three main types of symbiotic relationships: parasitism, commensalism, and mutualism. The first and the third can be key factors in the structure of a biological community; that is, all the populations of organisms living together and potentially interacting in a particular area. Parasitism is a kind of predator-prey relationship in which one organism, the parasite, derives its food at the expense of its symbiotic associate, the host. Parasites are usually smaller than their hosts. An example of a parasite is a tapeworm that lives inside the intestines of a larger animal and absorbs nutrients from its host. Natural selection favors the parasites that are best able to find and feed on hosts. At the same time, defensive abilities of hosts are also selected for. As an example, plants make chemicals toxic to fungal and bacterial parasites, along with ones toxic to predatory animals (sometimes they are the same chemicals). In vertebrates, the immune system provides a multiple defense against internal parasites. At times, it is actually possible to watch the effects of natural selection in host-parasite relationships. For example, Australia during the 1940 s was overrun by hundreds of millions of European rabbits. The rabbits destroyed huge expanses of Australia and threatened the sheep and cattle industries. In 1950, myxoma virus, a parasite that affects rabbits, was deliberately introduced into Australia to control the rabbit population. Spread rapidly by mosquitoes, the virus devastated the rabbit population. The virus was less deadly to the offspring of surviving rabbits, however, and it caused less and less harm over the years. Apparently, genotypes (the genetic make-up of an organism) in the rabbit population were selected that were better able to resist the parasite. Meanwhile, the deadliest strains of the virus perished with their hosts as natural selection favored strains that could infect hosts but not kill them. Thus, natural selection stabilized this host-parasite relationship. 問題： Paragraph 1: A symbiotic relationship is an interaction between two or more species in which one species lives in or on another species. There are three main types of symbiotic relationships: parasitism, commensalism, and mutualism. The first and the third can be key factors in the structure of a biological community; that is, all the populations of organisms living together and potentially interacting in a particular area. 1. Which of the following statements about commensalism can be inferred from paragraph 1? (3) It excludes interactions between more than two species. It makes it less likely for species within a community to survive. Its significance to the organization of biological communities is small. Its role in the structure of biological populations is a disruptive one. Paragraph 2: Parasitism is a kind of predator-prey relationship in which one organism, the parasite, derives its food at the expense of its symbiotic associate, the host. Parasites are usually smaller than their hosts. An example of a parasite is a tapeworm that lives inside the intestines of a larger animal and absorbs nutrients from its host. Natural selection favors the parasites that are best able to find and feed on hosts. At the same time, defensive abilities of hosts are also selected for. As an example, plants make chemicals toxic to fungal and bacterial parasites, along with ones toxic to predatory animals (sometimes they are the same chemicals). In vertebrates, the immune system provides a multiple defense against internal parasites. 2. The word derives in the passage is closest in meaning to (2) Digests Obtains Controls Discovers 3. According to paragraph 2. which of the following is true of the action of natural selection on hosts and parasites?(2) Hosts benefit more from natural selection than parasites do. Both aggression in predators and defensive capacities in hosts are favored for species survival. The ability to make toxic chemicals enables a parasite to find and isolate its host. Larger size equips a parasite to prey on smaller host organisms. . 36G資料百度云盤下載： 為防止惡意點擊下載，考生需要咨詢客服索取百度盤地址，只為真實需要的同學(xué)提供服務(wù)! 譯文： 參考譯文：共生關(guān)系 共生關(guān)系是兩種或更多物種之間的一種交互作用，其中一個物種要么在另一個物種中生存要么依賴另外一個物種生存。共生關(guān)系共有三種類型：寄生、共棲和互利共生。其中第一種和第三種是一個生物群落結(jié)構(gòu)的關(guān)鍵要素。所謂生物群落，指的是在某個特定區(qū)域內(nèi)，所有生物體共同生存并且潛在地相互影響。 寄生現(xiàn)象是一種捕食式的關(guān)系，其中，寄生物通過削弱其寄主而獲得自身所需食物。寄生物的形體往往小于寄主。絳蟲是寄生的例子之一，它生存在較大型動物的腸道中，并吸收寄主體內(nèi)的營養(yǎng)。自然選擇青睞那些尋找寄主并且寄生能力強(qiáng)的寄生蟲，同時，防御能力強(qiáng)的寄主也被選擇出來。比如說，有些植物會產(chǎn)生對真菌和細(xì)菌寄生物有毒的化學(xué)物質(zhì)，也會產(chǎn)生那些對捕食動物有毒的化學(xué)物質(zhì)(有時這些化學(xué)物質(zhì)是一樣的)。而對于脊椎動物來說，其身體的免疫系統(tǒng)可以對體內(nèi)的寄生物進(jìn)行多層防御。 有時候，寄生關(guān)系的自然選擇效應(yīng)也可能在現(xiàn)實中被觀察到。比如說，二十世紀(jì)四十年代，億萬只歐洲兔在澳大利亞泛濫成