2017年3月25托福答案解析考試真題

　　“托福”(TOEFL)這個詞對當今的中國年輕人來說,并不陌生?，F(xiàn)方便大家閱讀，整理了3月25日托福答案解析。下面就是學習啦小編給大家整理的2017年3月25日托?？荚嚧鸢附馕?，希望對你有用!

　　2017年3月25日托福聽力真題答案及解析

　　Conversation 1

　　話題分類： student and employee

　　內(nèi)容回憶： 學生問老師為什么我們學校沒有去西班牙的交換計劃，說自己朋友的大學就有西班牙留學的項目，老師說之前是有的，但是現(xiàn)在沒有了，現(xiàn)在只有為期一年的出國留學計劃。男生說一年的話就來不及完成別的必修課的學分了。老師說，如果申請留學計劃的話還可以申請獎學金，男生很吃驚，問老師做交換生可以有學分嗎?老師建議男生把西班牙學校的學習大綱發(fā)給她看看然后再決定能不能抵學分。

　　Conversation 2

　　話題分類 student and course advisor

　　內(nèi)容回憶： 女生去意大利進行藝術(shù)交流學習，回來之后發(fā)現(xiàn)想選的課取消了。問老師怎么辦，解決辦法是選一門low level course。老師建議女生想好自己想要研究的課題，然后聯(lián)系教授指導。之后學生還和老師進行了藝術(shù)方面的交流。

　　Lecture 1

　　學科分類：人類學

　　標題： sedentary lifestyle

　　內(nèi)容回憶： 早期的人類是以打獵和采集為生的，但是后來人類開始了sedentary lifestyle。 這種定居對生活有利有弊。好處是人類可以獲得更加穩(wěn)定的食物來源，種植大量的農(nóng)作物，但是也有缺點，例如相比狩獵和采集生活來說，定居生活的人類獲得的食物的營養(yǎng)非常單一。另外，如果發(fā)生自燃災(zāi)害，很可能顆粒無收，生活受到威脅。最后，人們和牲畜生活在一起的聚居生活，很容易引發(fā)傳染病。

　　Lecture 2

　　學科分類： Music History

　　標題： 巴洛克時期的音樂

　　內(nèi)容回憶： 講了巴洛克時期的音樂，受到了古希臘哲學家的影響。古希臘哲學家認為音樂可以塑造人的性格，還可以傳遞感情，巴洛克時期音樂的對比很強烈，還提到了兩種不同的音樂模式，一種音樂混合了多種旋律，旋律之間相互有聯(lián)系有彼此獨立。另一種音樂只有一種旋律，但是這種旋律很適合音樂劇獨白，因此這種形式通常出現(xiàn)在音樂劇中。

　　Lecture 3

　　學科分類： Geology

　　標題： Geothermal Energy地熱能

　　內(nèi)容回憶： 地熱能是一種天然的熱能，來自地球內(nèi)部的熔巖，可以導致火山爆發(fā)和地震。通過地下水，地熱可以被傳送到離地面比較近的地方。熔巖會加熱地下水，這些水最終會滲出地表。19世紀很多企業(yè)開始利用地熱能，但是在此之后，越來越多的公司開始利用靠近地表的地熱。為了監(jiān)控地熱能，科學家們想出了很多的辦法，例如在黃石公園，研究者們利用高空探測器，通過測量溫度來監(jiān)控地熱能。

　　Lecture 4

　　學科分類： Astronomy

　　標題： 行星探測

　　內(nèi)容回憶： 通常人們認為適合生存的行星必須要有水，有生命，這種行星離恒心的距離一般是比較固定的。但是最新的研究發(fā)現(xiàn)這并不一定。有些行星是氣體巨星，比地球大很多。有些行星距離恒星的距離太遠了。后來還提到了K18星球，以及如何發(fā)現(xiàn)。教授說還有可能會發(fā)現(xiàn)類似的星球，而且會距離地球更近一些。

　　2017年3月25日托福閱讀真題答案及解析

　　Passage One

　　學科分類：農(nóng)業(yè)類

　　題目：Soil Fertilization

　　內(nèi)容回憶： 真題Soil Fertilization

　　Fertilizers partially restore plant nutrients lost by erosion, crop harvesting, and leaching. Farmers can use either organic fertilizer from plant and animal materials or commercial inorganic fertilizer produced from various minerals. Three basic types of organic fertilizer are animal manure, green manure, and compost. Animal manure includes the waste matter of cattle, horses, poultry, and other farm animals. It improves soil structure, adds organic nitrogen, and stimulates beneficial soil bacteria and fungi.

　　Despite its effectiveness, the use of animal manure in the United States has decreased. There are three reasons for this: the replacement of most mixed animal-raising and crop-farming operations with separate operations for growing crops and raising animals, the high costs of transporting animal manure from feedlots near urban areas to distant rural crop-growing areas, and the replacement of horses and other draft animals that added manure to the soil with tractors and other motorized farm machinery.

　　Green manure is fresh or growing green vegetation plowed into the soil to increase the organic matter and humus (degraded organic matter) available to the next crop. Compost is a sweet-smelling, dark-brown, humuslike material that is rich in organic matter and soil nutrients. It is produced when microorganisms in soil (mostly fungi and aerobic bacteria) break down organic matter such as leaves, food wastes, paper, and wood in the presence of oxygen. Compost is a rich natural fertilizer and soil conditioner that aerates soil, improves its ability to retain water and nutrients, helps prevent erosion, and prevents nutrients from being wasted by being dumped in landfills. Compost is produced by piling up alternating layers of nitrogen-rich wastes (such as grass clippings, weeds, animal manure, and vegetable kitchen scraps), carbon-rich plant wastes (dead leaves, hay, straw, sawdust), and topsoil. Compost provides a home for microorganisms that help decompose plant and manure layers and reduces the amount of plant wastes taken to landfills and incinerators.

　　Another form of organic fertilizer is the spores of mushrooms, puffballs, and truffles. Rapidly growing and spreading mycorrhizae fungi in the spores attach to plant roots and help them take in moisture and nutrients from the soil. Unlike typical fertilizers that must be applied every few weeks, one application of mushroom fungi lasts all year and costs just pennies per plant. The fungi also produce a bigger root system, which makes plants more disease resistant.

　　Corn, tobacco, and cotton can deplete the topsoil of nutrients, especially nitrogen, if planted on the same land several years in a row. One way to reduce such losses is crop rotation. Farmers plant areas or strips with nutrient-depleting crops one year. In the next year they plant the same areas with legumes, whose root nodules add nitrogen to the soil. In addition to helping restore soil nutrients, this method reduces erosion by keeping the soil covered with vegetation and helps reduce crop losses to insects by presenting them with a changing target.

　　Today, many farmers rely on commercial inorganic fertilizers containing nitrogen (as ammonium ions, nitrate ions, or urea), phosphorus (as phosphate ions), and potassium (as potassium ions). Inorganic commercial fertilizers are easily transported, stored, and applied. Worldwide, their use increased about tenfold between 1950 and 1989 but declined by 12% between 1990 and 1999. Today, the additional food they help produce feeds one of every three people in the world, without them, world food output, would drop an estimated 40%.

　　Commercial inorganic fertilizers have some disadvantages, however. These include (1) not adding humus to the soil, (2) reducing the soil’s content of organic matter and thus its ability to hold water (unless animal manure and green manure are also added to the soil), (3) lowering the oxygen content of soil and keeping fertilizer from being taken up as efficiently, (4) typically supplying only two or three of the twenty or so nutrients needed by plants, and (5) releasing nitrous oxide, a greenhouse gas that can enhance global warming. The widespread use of commercial inorganic fertilizers, especially on sloped land near streams and lakes, also causes water pollution as nitrate and phosphate fertilizer nutrients are washed into nearby bodies of water. The resulting plant nutrient enrichment causes algae blooms that use up oxygen dissolved in the water, thereby killing fish.

　　Paragraph 1

　　Fertilizers partially restore plant nutrients lost by erosion, crop harvesting, and leaching. Farmers can use either organic fertilizer from plant and animal materials or commercial inorganic fertilizer produced from various minerals. Three basic types of organic fertilizer are animal manure, green manure, and compost. Animal manure includes the waste matter of cattle, horses, poultry, and other farm animals. It improves soil structure, adds organic nitrogen, and stimulates beneficial soil bacteria and fungi.

　　1、The word "beneficial" in the passage is closest in meaning to

　　necessary

　　helpful

　　several

　　hidden

　　Paragraph 2

　　Despite its effectiveness, the use of animal manure in the United States has decreased. There are three reasons for this: the replacement of most mixed animal-raising and crop-farming operations with separate operations for growing crops and raising animals, the high costs of transporting animal manure from feedlots near urban areas to distant rural crop-growing areas, and the replacement of horses and other draft animals that added manure to the soil with tractors and other motorized farm machinery.

　　2、According to paragraph 2, all of the following contributed to the decrease in the use of animal manure in the United States EXCEPT

　　changes in crop-farming and animal-raising operations

　　high transportation costs

　　the movement or large numbers of feedlots to distant rural areas

　　the introduction of motorized farm machinery

　　Paragraph 3

　　Green manure is fresh or growing green vegetation plowed into the soil to increase the organic matter and humus (degraded organic matter) available to the next crop. Compost is a sweet-smelling, dark-brown, humuslike material that is rich in organic matter and soil nutrients. It is produced when microorganisms in soil (mostly fungi and aerobic bacteria) break down organic matter such as leaves, food wastes, paper, and wood in the presence of oxygen. Compost is a rich natural fertilizer and soil conditioner that aerates soil, improves its ability to retain water and nutrients, helps prevent erosion, and prevents nutrients from being wasted by being dumped in landfills. Compost is produced by piling up alternating layers of nitrogen-rich wastes (such as grass clippings, weeds, animal manure, and vegetable kitchen scraps), carbon-rich plant wastes (dead leaves, hay, straw, sawdust), and topsoil. Compost provides a home for microorganisms that help decompose plant and manure layers and reduces the amount of plant wastes taken to landfills and incinerators.

　　3、According to paragraph 3, what is one advantage of using compost in raising crops?

　　It makes the soil easier to plow in preparation for planting.

　　Water and nutrients stay in the soil and enable plant growth.

　　The damage to soil from microorganisms is reduced.

　　Excess oxygen is removed from the soil.

　　4、According to paragraph 3, one important physical effect of compost is that it

　　adds an oxygen-rich layer to the layers rich in nitrogen and carbon

　　decreases the quantity of plant material that needs to be discarded

　　helps keep the same amount of moisture in each layer of soil

　　reduces the amount of fungi and aerobic bacteria in the pile

　　Paragraph 4

　　Another form of organic fertilizer is the spores of mushrooms, puffballs, and truffles.

　　Rapidly growing and spreading mycorrhizae fungi in the spores attach to plant roots and help them take in moisture and nutrients from the soil. Unlike typical fertilizers that must be applied every few weeks, one application of mushroom fungi lasts all year and costs just pennies per plant. The fungi also produce a bigger root system, which makes plants more disease resistant.

　　5、According to paragraph 4, each of the following is an advantage of using mushroom spores as fertilizer EXCEPT:

　　The cost of using mushroom spores is relatively low.

　　A single application of mushroom spores is enough for a whole year.

　　Mushroom fungi are nutrients that plants can take in easily.

　　Mushroom fungi help protect plants from disease.

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