考试日期：2014年6月29日

Reading Passage 1

Title:

动物眼睛的起源

Question types:

文章内容回顾：

主题：生物类话题

本文讲述了生物眼睛的进化，说最早的眼睛可能是源于一些单细胞什么的，用途是捕捉光源。之后给出一些证据和考古发现证明某一时期动物眼睛的发展，最后说这可能并不是最早的眼睛。

难度分析：

生物类话题是托福考试永恒的高频题，尤其是动物类学科。相信大多数考生在生物学方面词汇都有大量积累，本文讲述的动物眼睛的起源，做题时要注意不同的理论依据和它的相应解释。

相关背景内容：

The earliest predecessors of the eye were photoreceptor proteins that sense light, found even in unicellular organisms, called "eyespots". Eyespots can only sense ambient brightness: they can distinguish light from dark, sufficient for photoperiodism and daily synchronization of circadian rhythms. They are insufficient for vision, as they cannot distinguish shapes or determine the direction light is coming from. Eyespots are found in nearly all major animal groups, and are common among unicellular organisms, including euglena. The euglena's eyespot, called a stigma, is located at its anterior end. It is a small splotch of red pigment which shades a collection of light sensitive crystals. Together with the leading flagellum, the eyespot allows the organism to move in response to light, often toward the light to assist in photosynthesis, and to predict day and night, the primary function of circadian rhythms. Visual pigments are located in the brains of more complex organisms, and are thought to have a role in synchronising spawning with lunar cycles. By detecting the subtle changes in night-time illumination, organisms could synchronise the release of sperm and eggs to maximise the probability of fertilisation.

Vision itself relies on a basic biochemistry which is common to all eyes. However, how this biochemical toolkit is used to interpret an organism's environment varies widely: eyes have a wide range of structures and forms, all of which have evolved quite late relative to the underlying proteins and molecules.

At a cellular level, there appear to be two main "designs" of eyes, one possessed by the protostomes (molluscs, annelid worms and arthropods), the other by the deuterostomes (chordates and echinoderms).

The functional unit of the eye is the receptor cell, which contains the opsin proteins and responds to light by initiating a nerve impulse. The light sensitive opsins are borne on a hairy layer, to maximise the surface area. The nature of these "hairs" differs, with two basic forms underlying photoreceptor structure: microvilli and cilia. In the protostomes, they are microvilli: extensions or protrusions of the cellular membrane. But in the deuterostomes, they are derived from cilia, which are separate structures. The actual derivation may be more complicated, as some microvilli contain traces of cilia — but other observations appear to support a fundamental difference between protostomes and deuterostomes.These considerations centre on the response of the cells to light – some use sodium to cause the electric signal that will form a nerve impulse, and others use potassium; further, protostomes on the whole construct a signal by allowing more sodium to pass through their cell walls, whereas deuterostomes allow less through.

This suggests that when the two lineages diverged in the Precambrian, they had only very primitive light receptors, which developed into more complex eyes independently.

Reading Passage 2

Title:

性别地位的变化

Question types:

文章内容回顾：

主题：农业历史类话题

本文主要讲述了随着农业的发展男女社会地位的变化。在早期H农业时主力军是女性，所以她们享受着较高的社会地位。之后随着农业的发展，特别是plow的出现男女开始分工，男性包办主要的农活，而女性则主要负责一些复产业比如纺纱之类的。男性地位显著提高。此外还介绍了一些不同地区同一时期男女分工的差别。

难度分析：

历史题材类文章。讲述了不同发展阶段由于农业的变化导致女性和男性的社会地位也在不断发生变化。文章按照时间顺序展开，阅读量较大的同学应该对这一背景和题材并不陌生。考生要善于抓住历史演进的主线，把握文明发展的进程，特别注意细节题的一一对应。。

相关背景内容：

The gender division of labour varies significantly across societies. In some cultures women actively participate in employment outside of the home, while in others there is a clear specialisation of tasks along gender lines with women tending to stay at home while their husbands go out to earn the money. These differences are most clearly illustrated by the vast differences in female labour force participation, which in 2000 ranged from 16.1% in Pakistan to 90.5% in Burundi.

Many determinants of these differences have been thoroughly studied, including per capita income and the specialisation of the economy in female-friendly industries. However, even controlling for these variables there remain important time-invariant differences in gender roles.

A number of scholars have argued that these differences can be explained by cultural values. However this leaves the questions of where these values come from. Ester Boserup (1970) in her path-breaking book Women’s Role in Economic Development argues that gender role differences have their origins in different forms of agriculture practiced traditionally.

In particular, she identifies important differences between shifting and plough cultivation. The former, which uses hand-held tools like the hoe and the digging stick, is labour intensive and women actively participate in farm work. The latter, in contrast, is more capital intensive, using the plough to prepare the soil. Unlike the hoe or digging stick, the plough requires significant upper body strength, grip strength, and burst of power, which are needed to either pull the plough or control the animal that pulls it.

Because of these requirements, when plough agriculture is practiced, men have an advantage in farming relative to women. Also reinforcing this gender-bias in ability is the fact that when the plough is used, there is less need for weeding, a task typically undertaken by women and children. In addition, child-care, a task almost universally performed by women, is most compatible with activities that can be stopped and resumed easily and do not put children in danger. These are characteristics that are satisfied for hoe agriculture, but not for plough agriculture since large animals are typically used to pull the plough.

Reading Passage 3

Title:

欧洲人口增长

Question types:

文章内容回顾：

主题：社会历史类话题

本文讲述了18、19世纪欧洲人口增长，有几个原因共同导致，如农业和工业的发展等。人们的生活质量也是当时世界上最高水平。科技和农业项目的研究应用、便利的交通等都是促进因素。虽然其中城市人口死亡率有过一段居高不下的时期，但是在改善城市生活环境后，得到了明显改善。

难度分析：

社会类话题。文中涉及到了此类话题常考的一系列因素，如农业和工业发展对社会的影响，人口数量的变化，城市化等问题，

相关背景内容：

After a century of virtually no population growth, the countries of Western Europe experienced dramatic population increases between 1750 and 1800. Many countries doubled in size. In some countries, the growth continued through the nineteenth century. The population of Great Britain, for instance, doubled between 1750 and 1800 and then tripled between 1800 and 1900.

There were several reasons for the sudden increase. Medical advances and improved hygiene limited the devastation caused by epidemic diseases and plagues. The introduction of new food crops, most notably the potato, provided a better diet for the poor and reduced the incidence of famine. The combination of greater public order and fewer civil wars meant that life was less hazardous. The net result was a lower death rate and soaring populations.

The growing population, with a rising proportion of children to raise and older people to care for, put increased pressure on every aspect of society. Many peasants were no longer able to provide land for their children, who were forced to look for other ways to make their living. Small artisans in the cities suffered similar problems, unable to provide places for their children in their own workshops.

The exact relationship between population growth and industrialization is unclear, though the two are clearly intertwined. (Even countries that were late to industrialize shared in the general population increase, and its related problems.) What is clear is that the growth in population increased the demand for both food and manufactured goods and provided an abundance of cheap labor to produce them.