Đề thi chính thức THPT Quốc gia môn Tiếng Anh năm 2015

Library is a collection of books and other informational materials made available to people for reading, study, or reference. The word library comes (28)......liber, the Latin word for "book”. (29)......, library collections have almost always contained a variety of materials. Contemporary libraries maintain collections that include not only printed materials such as manuscripts, books, newspapers, and magazines, (30)...... audio visual and online databases. In addition (31)......maintaining collections within library buildings, modern libraries often feature tele-communications links that provide users with access to information at remote sites.

The central mission of a library (32)......to collect, organise, preserve, and provide access to knowledge and information. In fulfilling this mission, libraries preserve a valuable record of culture that can be passed down to (33)......generations. Libraries are an essential link in this communication between the past, present, and future. Whether the cultural record is contained in books or in electronic formats, libraries ensure (34)......the record is preserved and made available for later use.

People use library resources to gain information about personal (35)......or to obtain recreational materials such as films and novels. Students use libraries to supplement and enhance their classroom experiences, to learn (36)..... in locating sources of information, and to develop good reading and study habits. Public officials use libraries to research legislation and public policy issues. One of the most valued of all cultural institutions, the library (37).....information and services that are essential to learning and progress.

From “Library (institution)” by Richard S. Halsey et al.

Plants and animals will find it difficult to escape from or adjust to the effects of global warming. Scientists have already observed shifts in the lifecycles of many plants and animats, such as flowers blooming earlier and birds hatching earlier in the spring. Many species have begun shifting where they live or their annual migration patterns due to warmer temperatures.

With further warming, animals will tend to migrate towards the poles and up mountainsides towards higher elevations. Plants will also attempt to shift their ranges, seeking new areas as old habitats grew too warm. In many places, however, human development will prevent these shifts. Species that find cities or farmland blocking their way north or south may become extinct. Species living in unique ecosystems, such as those found in polar and mountaintop regions, are especially at risk because migration to new habitats is not possible. For example, polar bears and marine mammals in the Arctic are already threatened by dwindling sea ice but have nowhere farther north to go.

Projecting species extinction due to global warming is extremely difficult. Some scientists have estimated that 20 to 50 percent of species could be committed to extinction with 2 to 3 Celsius degrees of further wanning. The rate of warming, not just the magnitude, is extremely important for plants and animals. Some species and even entire ecosystems, such as certain types of forest, may not be able to adjust quickly enough and may disappear.

Ocean ecosystems, especially fragile ones like coral reek, will also be affected by global warming, warmer ocean temperatures can cause coral to "bleach", a state which if prolonged will lead to the death of the coral. Scienists estimate that even 1 Celsius degree of additional warming could lead to widespead bleaching and death of coral reefs around the world. Also, increasing carbon dioxide in the atmosphere enters the ocean and increases the acidity of ocean waters. This acidification further stresses ocean ecosystems.

From “Global Warming” by Michael Mastrandrea and Stephen H. Schneider

Overpopulation, the situation of having large numbers of people with too few resources and too little space, is closely associated with poverty. It can result from high population density, or from low amounts of resources, or from both. Excessively high population densities put stress on available resources. Only a certain number of people can be supported on a given area of land, and that number depends on how much food and other resources the land can provide. In countries where people live primarily by means of simple fanning, gardening, herding, hunting, and gathering, even large areas of land can support only small numbers of people because these labour intensive subsistence activities produce only small amounts of food.

In developed countries such as the United States, Japan, and the countries of Western Europe, overpopulation generally is not considered a major cause of poverty. These countries produce large quantitics of food through mechanized farming, which depends on commercial fertilizers, large-scale irrigation, and agricultural machinery. This form of production provides enough food to support the high densities of people in metropolitan areas.

A country’s level of poverty can depend greatly on its mix of population density and agricultural productivity. Bangladesh, for example, has one of the world’s highest population densities, with 1,147 persons per sq km. A large majority of the people of Bangladesh engage in low - productivity manual farming, which contributes to the country's extremely high level of poverty. Some of the smaller countries in Western Europe, such as the Netherlands and Belgium, have high population densities as well. These countries practise mechanized farming and are involved in high-tech industries, however, and therefore have high standards of living.

At the other end of the spectrum, many countries in sub-Saharan Africa have population densities of less than 30 persons per sq km. Many people in these countries practise manual subsistence farming; these countries also have infertile land, and lack the economic resources and technology to boost productivity. As a consequence, these nations are very poor. The United Slates has both relatively low population density and high agricultural productivity; it is one of the world's wealthiest nations.

High birth rates contribute to overpopulation in many developing countries. Children are assets to many poor families because the provide labour, usually for farming. Cultural norms in traditionally rural societies commonly sanction the value of large families. Also, the governments of developing countries often provide little or no support, financial or political, for family planning; even people who wish to keep their families small have difficulty doing so. For all these reasons, developing countries lend to have high rates of population growth.