Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 34 to 40.

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities. However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, has a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

For which of the following reasons can natural pollutants play an important role in controlling air pollution?

A. They function as part of a purification process

B. They occur in greater quantities than other pollutants

C. They are less harmful to living beings than other pollutants

D. They have existed since the Earth developed

Cho tam giác ABC và M là một điểm nằm trong tam giác. Gọi I là giao điểm của đường thẳng BM và cạnh AC.

So sánh IB với IC + CB, từ đó chứng minh IB + IA < CA + CB.

ABCD là một hình vuông cạnh 12cm, AE = xcm (h123). Tính x sao cho diện tích tam giác ABE bằng 1/3 diện tích hình vuông ABCD.

Mark the letter A, B, C, or D on your answer sheet to indicate the word(s) OPPOSITE in meaning to the underlined word(s) in each of the following questions.

She was the child of a broken marriage

A. broken 

B. disastrous 

C. happy 

D. failed

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

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 animals, 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 toward the poles and up mountainsides toward higher elevations. Plants will also attempt to shift their ranges, seeking new areas as old habitats grow 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 warming. 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 reefs, 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. Scientists estimate that even 1 Celsius degree of additional warming could lead to widespread 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.

Scientists have observed that warmer temperatures in the spring cause flowers to ______.

A. die instantly 

B. bloom earlier 

C. become lighter 

D. lose color 

Tia tử ngoại tác động đến quá trình sinh trưởng của trẻ nhỏ như thế nào?

A. Các dạng tia tử ngoại gây ra còi cọc, chậm lớn ở trẻ sơ sinh và trẻ nhỏ

B. Tia tử ngoại hỗ trợ quá trình tiêu hóa và hấp thu canxi từ thức ăn khiến trẻ nhanh lớn

C. Tia tử ngoại thúc đẩy biến tiền vitamin D thành vitamin D, vitamin này thúc đẩy quá trình chuyển hóa canxi và tạo xương.

D. Tia tử ngoại chuyển canxi vô cơ thành canxi hữu cơ và thúc đẩy quá trình tạo xương

Trong một khu vườn cây ăn quả (trái), nhân tố vô sinh là:

A. Chiếc lá rụng

B. Cây mít

C. Con bọ ngựa

D. Con xén tóc

Read the following passage on transport, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

The Sun today is a yellow dwarf star. It is fueled by thermonuclear reactions near its center that convert hydrogen to helium. The Sun has existed in its present state for about four billion six hundred million years and is thousands of times larger than the Earth.

By studying other stars, astronomers can predict what the rest of the Sun’s life will be like. About five billion years from now, the core of the Sun will shrink and become hotter. The surface temperature will fall. The higher temperature of the center will increase the rate of thermonuclear reactions. The outer regions of the Sun will expand approximately 35 million miles, about the distance to Mercury, which is the closest planet to the Sun. The Sun will then be a red giant star. Temperatures on the Earth will become too high for life to exist.

Once the Sun has used up its thermonuclear energy as a red giant, it will begin to shrink. After it shrinks to the size of the Earth, it will become a white dwarf star. The Sun may throw off huge amounts of gases in violent eruptions called nova explosions as it changes from a red giant to a white dwarf.

After billions of years as a white dwarf, the Sun will have used up all its fuel and will have lost its heat. Such a star is called a black dwarf. After the Sun has become a black dwarf, the Earth will be dark and cold. If any atmosphere remains there, it will have frozen over the Earth’s surface.

As a white dwarf, the Sun will be _______.

A. a cool and habitable planet

B. the same size as the planet Mercury

C. thousands of times smaller than it is today       

D. around 35 million miles in diameter

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 38 to 42.

(1) A small but growing group of scholars, evolutionary psychologists, are beginning to sketch the contours of the human mind as designed by natural selection. Some of them even anticipate the coming of a field called “mismatch theory”, which would study maladies resulting from contrasts between the modern environment and the “ancestral environment”. The one we were designed for.

(2) There is no shortage of such maladies to study. Rates of depression have been doubling in some industrial countries roughly every 10 years. Suicide is the third most common cause of death among young adults, after car wrecks and homicides.

(3) Evolutionary psychology is a long way from explaining all this with precision, but it is already shedding enough light to challenge some conventional wisdom. It suggests, for example, that the nostalgia for the nuclear family of the 1950s is in some way misguided that the model family of husband at work and wife at home is hardly a “natural” and the healthful living arrangement, especially for the wives. Moreover, the by gone lifestyles that do look fairly by commercialism. Perhaps the biggest surprise from evolutionary psychology is it depiction of the “animal” is us. Freud, and various thinkers since, saw “civilization” as an oppressive force that thwarts basic animal instincts and urges and transmutes them into psychopathology. However, evolutionary psychology suggests that a large threat to mental health may be the way civilization thwarts civility. There is a gentler, kinder side of human nature, and it seems increasingly to be a victim of repression in modern society.

Which of the following is the theory that evolutionary psychologists forecast about its appearance?

A. Ancestral environment theory

B. Modern environment theory 

C. Civilization theory

D. Mismatch theory