2017年4月10日托福考试阅读_托福口语复议

雅思托福考试都是出国留学类的语言考试，也是实用性英语的考试，所以和中国的英语考试有很大的不同，对于想要出国留学的学生来说，必须要好好的备考托福了，今天沪江的小编为大家准备了实用的真题测练、经典加试，以及词汇题汇总。这些内容都非常的完整，有英文原文和答案，希望考生们可以好好阅读。

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

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

A. necessary

B. helpful

C. several

D. hidden

2017年4月托福考试阅读机经之经典加试(部分内容)：

苏美尔文明

It is an astonishing fact that human civilization should have emerged into the light of history in two separate places at just about the same time. Between 3,500 and 3,000 B.C. when Egypt was being united under pharaonic rule, another great civilization arose in Mesopotamia, the “land between the rivers”. And for close to three thousand years, the two rival centers retained their distinct characters, even though they had contact with each other from their earliest beginnings, and their destinies were interwoven in many ways. The pressure that forced the inhabitants of both regions to abandon the pattern of Neolithic village life may well have been the same. But the valley of the Tigris and Euphrates rivers, unlike that of the Nile, is not a narrow fertile strip protected by desert on either side. It resembles a wide, shallow trough with few natural defenses, crisscrossed by two great rivers and their tributaries, and is easily encroached upon from any direction.

Thus the facts of geography tend to discourage the idea of uniting the entire Mesopotamian area under a single head. Rulers who had this ambition did not appear, so far as we know, until about a thousand years after the beginnings of Mesopotamian civilization, and they succeeded in carrying it out only for brief periods and at the cost of almost continuous warfare. As a consequence, the political history of ancient Mesopotamia has no underlying theme of the sort that divine kingship provides for Egypt. Local rivalries, foreign incursions, the sudden upsurge and equally sudden collapse of military power – these are its substance.

The origin of the Sumerians remains obscure. Their language is unrelated to any other known tongue. Sometimes before 4,000 B.C. they came to southern Mesopotamia, from Persia, and there, within the next thousand years, they founded a number of city-states and developed their distinctive form of writing in cuneiform (wedge-shaped) characters on clay tablets. Unfortunately, the tangible remains of Sumerian civilization are extremely scanty compared to those of ancient Egypt. Building stone being unavailable in Mesopotamia, the Sumerians used mud brick and wood, so that almost nothing is left of their architecture except the foundation. Nor did they share the Egyptians’ concern with the hereafter, although some richly endowed tombs in the shape of vaulted chambers below ground from the early dynastic period have been found in the city of Ur. Our knowledge of Sumerian Civilization thus depends very largely on chance fragments brought to light by excavation, including vast numbers of inscribed clay tablets. Yet we have learned enough to form a general picture of this vigorous, inventive, and disciplined people.

Each Sumerian city-state had its own local god, who was regarded as its king and owner. It also had a human ruler, the steward of the divine sovereign, who led the people in serving the deity. The local god, in turn, was expected to plead the cause of his subjects among his follow deities who controlled the forces of nature such as wind and weather, water, fertility, and the heavenly bodies. Nor was the idea of divine ownership treated as a mere pious fiction. The god was quite literally believed to own not only the territory of the city-state but also the labor power of the population and its products. All these were subject to his commands, transmitted to people by his human steward. The result was an economic system. The temple controlled the pooling of labor and resources for communal enterprises, such as the building of dikes or irrigation ditches, and it collected and distributed a considerable part of the harvest. All this required the keeping of detailed written records. Hence, we need not be surprised to find that the texts of early Sumerian inscriptions deal very largely with economic and administrative rather than religious matters, although writing was a priestly privilege.

题目：(答案在最后)

1. The word astonishing in the passage is closest in meaning to

(A) important

(B) unknown

(D) interesting