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.

        In this era of increased global warming and diminishing fossil fuel supplies, we must begin to put a greater priority on harnessing alternative energy sources. Fortunately, there are a number of readily available, renewable resources that are both cost- effective and earth - friendly. Two such resources are solar power and geothermal power.

        Solar energy, which reaches the earth through sunlight, is so abundant that it could meet the needs of worldwide energy consumption 6,000 times over. And solar energy is easily harnessed through the use of photovoltaic cells that convert sunlight to electricity. In the US alone, more than 100, 000 homes are equipped with solar electric systems in the form of solar panels or solar roof tiles. And in other parts of the world, including many developing countries, the use of solar system is growing steadily.

       Another alternative energy source, which is abundant in specific geographical areas, is geothermal power, which creates energy by tapping heat from below the surface of the earth. Hot water and steam that are trapped in underground pools are pumped to the surface and used to run a generator, which produces electricity. Geothermal energy is 50,000 times more abundant than the entire known supply of fossil fuel resources and as with solar power, the technology needed to utilize geothermal energy is fairly simple. A prime example of effective geothermal use in Iceland, a region of high geothermal activity where there are over 80 percent of private homes, are heated by geothermal power.

       Solar and geothermal energy are just two of promising renewable alternatives to conventional energy sources. The time is long overdue to invest in the development and use of alternative energy on global scale.

According to the passage, how is solar energy production similar to geothermal energy production?

A. They both require the use of a generator.

B. They both use heat from the earth’s surface

C. They both require fairly simple technology.

D. They are both conventional and costly.

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 30 to 37.

        The Roman alphabet took thousands of years to develop, from the picture writing of the ancient Egyptians through modifications by Phoenicians, Greek, Romans, and others. Yet in just a dozen years, one man, Sequoyah, invented an alphabet for the Cherokee people. Bom in eastern Tennessee, Sequoyah was a hunter and a silversmith in his youth, as well as an able interpreter who knew Spanish, French and English.

        Sequoyah wanted his people to have the secret of the “talking leaves” as he called his books of white people, and so he set out to design a written form of Cherokee. His chief aim was to record his people’s ancient tribal customs. He began by designing pictographs for every word in the Cherokee vocabulary. Reputedly his wife, angry with him for his neglect of garden and house, burned his notes, and he had to start over. This time, having concluded that picture-writing was cumbersome, he made symbols for the sounds of Cherokee language. Eventually he refined his system to eighty-five characters, which he borrowed from the Roman, Greek, and Hebrew alphabets. He presented this system to the Cherokee General Council in 1821, and it was wholeheartedly approved. The response was phenomenal. Cherokees who had stmggled for months to leam English lettering school picked up the new system in days. Several books were printed in Cherokee, and in 1828, a newspaper, the Cherokee Phoenix, was first published in the new alphabet. Sequoyah was acclaimed by his people.

         In his later life, Sequoyah dedicated himself to the general advancement of his people. He went to Washington, D.C, as a representative of the Western tribes. He helped settled bitter differences among Cherokee after their forced movement by the federal government to the Oklahoma territory in the 1930s. He died in Mexico in 1843 while searching for groups of lost Cherokee. A statue of Sequoyah represents Oklahoma in the Statuary Hall in the Capitol building of Washington, DC. However, he is probably chiefly remembered today because Sequoias, the giant redwood trees of California, are named of him.

Why does author mention the giant redwood trees of California in the passage?

A. The trees inspired Sequoyah to write a book.

B. Sequoyah was bom in the vicinity of the redwood forest.

C. The trees were named in Sequoyah’s honor.

D. Sequoyah took his name from those trees.

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 30 to 37.

        The Roman alphabet took thousands of years to develop, from the picture writing of the ancient Egyptians through modifications by Phoenicians, Greek, Romans, and others. Yet in just a dozen years, one man, Sequoyah, invented an alphabet for the Cherokee people. Bom in eastern Tennessee, Sequoyah was a hunter and a silversmith in his youth, as well as an able interpreter who knew Spanish, French and English.

        Sequoyah wanted his people to have the secret of the “talking leaves” as he called his books of white people, and so he set out to design a written form of Cherokee. His chief aim was to record his people’s ancient tribal customs. He began by designing pictographs for every word in the Cherokee vocabulary. Reputedly his wife, angry with him for his neglect of garden and house, burned his notes, and he had to start over. This time, having concluded that picture-writing was cumbersome, he made symbols for the sounds of Cherokee language. Eventually he refined his system to eighty-five characters, which he borrowed from the Roman, Greek, and Hebrew alphabets. He presented this system to the Cherokee General Council in 1821, and it was wholeheartedly approved. The response was phenomenal. Cherokees who had stmggled for months to leam English lettering school picked up the new system in days. Several books were printed in Cherokee, and in 1828, a newspaper, the Cherokee Phoenix, was first published in the new alphabet. Sequoyah was acclaimed by his people.

         In his later life, Sequoyah dedicated himself to the general advancement of his people. He went to Washington, D.C, as a representative of the Western tribes. He helped settled bitter differences among Cherokee after their forced movement by the federal government to the Oklahoma territory in the 1930s. He died in Mexico in 1843 while searching for groups of lost Cherokee. A statue of Sequoyah represents Oklahoma in the Statuary Hall in the Capitol building of Washington, DC. However, he is probably chiefly remembered today because Sequoias, the giant redwood trees of California, are named of him.

In the final version of the Cherokee alphabet system, each of the characters represents a

A. picture

B. sound

C. word

D. thought

Viết các tích sau dưới dạng lũy thừa: 3.27.9

Tìm tất cả các số tự nhiên có hai chữ số là ước của :

a) 93;

b) 102;

c)120

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 35 to 42.

Life in the Universe

   Exobiology is the study of life that originates from outside of Earth. As yet, of course, no such life forms have been found. Exobiologists, however, have done important work in the theoretical study of where life is most likely to evolve, and what those extrateưestrial life forms might be like.

   What sorts of planets are most likely to develop life? Most scientists agree that a habitable planet must be terrestrial, or rock-based, with liquid surface water and biogeochemical cycles that somewhat resemble Earth’s. Water is an important solvent involved in many biological processes. Biogeochemical cycles are the continuous movement and transformation of materials in the environment. These cycles include the circulation of elements and nutrients upon which life and the Earth’s climate depend. Since (as far as we know) all life is carbon-based, a stable carbon cycle is especially important.

   The habitable zone is the region around a star in which planets can develop life. Assuming the need for liquid surface water, it follows that most stars around the size of our sun will be able to sustain habitable zones for billions of years. Stars that are larger than the sun are much hotter and bum out more quickly; life there may not have enough time to evolve. Stars that are smaller than the sun have different problem. First of all, planets in their habitable zones will be so close to the star that they will be “tidally locked” – that is one side of the planet will always face the star in perpetual daylight with the other side in the perpetual night. Another possible obstacle to life on smaller stars is that they tend to vary in their luminosity, or brightness, due to flares and “star spots”. The variation can be large enough to have harmful effects on the ecosystem.

   Of course, not all stars of the right size will give rise to life; they also must have terrestrial planets with the right kind of orbits. Most solar systems have more than one planet, which influence each other’s orbits with their own gravity. Therefore, in order to have a stable system with no planets flying out into space, the orbits must be a good distance from one another. Interestingly, the amount of space needed is roughly the width of a star’s habitable zone. This means that for life to evolve, the largest possible number of life-supporting planets in any star’s habitable zone is two.

   Finally, not all planets meeting the above conditions will necessarily develop life. One major threat is large, frequent asteroid and comet impacts, which will wipe out life each time it tries to evolve. The case of Earth teaches that having large gas giants, such as Saturn and Jupiter,.in the outer part of the solar system can help keep a planet safe for life. Due to their strong gravitation, they tend to catch or deflect large objects before they can reach Earth.

In order for life to develop, a planet’s orbit must not be

A. stable

B. very close to another planet’s orbit 

C. on the same planet as another planet’s orbit

D. less wide than the star’s habitable zone