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.

  Biological diversity has become widely recognized as a critical conservation issue only in the past two decades. The rapid destruction of the tropical rain forests, which are the ecosystems with the highest known species diversity on Earth, has awakened people to the importance and fragility of biological diversity. The high rate of species extinctions in these environments is jolting, but it is important to recognize the significance of biological diversity in all ecosystems. As the human population continues to expand, it will negatively affect one after another of Earth’s ecosystems. In terrestrial ecosystems and in fringe marine ecosystems (such as wetlands), the most common problem is habitat destruction. In most situations, the result is irreversible. Now humans are beginning to destroy marine ecosystems through other types of activities, such as disposal and runoff of poisonous waste; in less than two centuries, by significantly reducing the variety of species on Earth, they have irrevocably redirected the course of evolution.

  Certainly, there have been periods in Earth’s history when mass extinctions have occurred. The extinction of the dinosaurs was caused by some physical event, either climatic or cosmic. There have also been less dramatic extinctions, as when natural competition between species reached an extreme conclusion. Only 0.01 percent of the species that have lived on Earth have survived to the present, and it was largely chance that determined which species survived and which died out.

  However, nothing has ever equaled the magnitude and speed with which the human species is altering the physical and chemical world and demolishing the environment. In fact, there is wide agreement that it is the rate of change humans are inflicting, even more than the changes themselves, that will lead to biological devastation. Life on Earth has continually been in flux as slow physical and chemical changes have occurred on Earth, but life needs time to adapt-time for migration and genetic adaptation within existing species and time for the proliferation of new genetic material and new species that may be able to survive in new environments.

According to the passage, natural evolutionary change is different from changes caused by humans in that changes caused by humans _____________ .

A. affect fewer ecosystems

B. are occurring at a much faster rate

C. are reversible

D. are less devastating to most species

Tìm tập hợp các số nguyên x sao cho -2  ⋮ 3x - 1

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 28 to 34.

  It is said that George Washington was one of the first to realize how important the building of canals would be to the nation’s development. In fact, before he became the President, he headed the first company in the United States to build a canal, which was to connect the Ohio and Potomac rivers. It was never completed, but it showed the nation the feasibility of canals. As the country expanded westward, settlers in western New York, Pennsylvania, and Ohio needed a means to ship goods. Canals linking natural waterways seemed to supply an effective method.

  In 1791, engineers commissioned by the state of New York investigated the possibility of a canal between Albany on the Hudson River and Buffalo on Lake Eric to link the Great Lakes area with the Atlantic seacoast. It would avoid the mountains that served as a barrier to canals from the Delaware and Potomac rivers.

  The first attempt to dig the canal, to be called the Eric Canal, was made by private companies but only a comparatively small portion was built before the project was halted for lack of funds. The cost of the prospect was estimated $5 million, an enormous amount for those days. There was some on-again-off-again federal funding, but this time the War of 1812 put an end to construction. In 1817, DeWitt Clinton was elected Governor of New York and persuaded the state to finance and build the canal. It was completed in 1825, costing $2 million more than expected.

  The canal rapidly lived up to its sponsors’ faith, quickly paying for itself through tolls. It was far more economical than any other form of transportation at the time. It permitted trade between the Great Lake region and the East coast, robbing the Mississippi River of much of its traffic. It allowed New York to supplant Boston, Philadelphia, and other eastern cities as the chief center of both domestic and foreign commerce. Cities sprang up along the canal. It also contributed in a number of ways to the North’s victory over the South in the Civil War.

  An expansion of the canal was planned in 1849. Increased traffic would undoubtedly have warranted its construction had it not been for the railroads.

Which of the following is NOT given as an effect of the building of the Eric Canal in paragraph 4?

A. It took water traffic away from the Mississippi River

B. It established Boston and Philadelphia as the most important centers of trade

C. It helped determine the outcome of the Civil War

D. It allowed the East coast to trade with the Great Lake Sea

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 28 to 34.

  It is said that George Washington was one of the first to realize how important the building of canals would be to the nation’s development. In fact, before he became the President, he headed the first company in the United States to build a canal, which was to connect the Ohio and Potomac rivers. It was never completed, but it showed the nation the feasibility of canals. As the country expanded westward, settlers in western New York, Pennsylvania, and Ohio needed a means to ship goods. Canals linking natural waterways seemed to supply an effective method.

  In 1791, engineers commissioned by the state of New York investigated the possibility of a canal between Albany on the Hudson River and Buffalo on Lake Eric to link the Great Lakes area with the Atlantic seacoast. It would avoid the mountains that served as a barrier to canals from the Delaware and Potomac rivers.

  The first attempt to dig the canal, to be called the Eric Canal, was made by private companies but only a comparatively small portion was built before the project was halted for lack of funds. The cost of the prospect was estimated $5 million, an enormous amount for those days. There was some on-again-off-again federal funding, but this time the War of 1812 put an end to construction. In 1817, DeWitt Clinton was elected Governor of New York and persuaded the state to finance and build the canal. It was completed in 1825, costing $2 million more than expected.

  The canal rapidly lived up to its sponsors’ faith, quickly paying for itself through tolls. It was far more economical than any other form of transportation at the time. It permitted trade between the Great Lake region and the East coast, robbing the Mississippi River of much of its traffic. It allowed New York to supplant Boston, Philadelphia, and other eastern cities as the chief center of both domestic and foreign commerce. Cities sprang up along the canal. It also contributed in a number of ways to the North’s victory over the South in the Civil War.

  An expansion of the canal was planned in 1849. Increased traffic would undoubtedly have warranted its construction had it not been for the railroads.

The actual cost of building the Eric Canal was ____.

A. $5 million

B. less than had been expected

C. $7 million 

D. more than could be repaid

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 28 to 34.

  It is said that George Washington was one of the first to realize how important the building of canals would be to the nation’s development. In fact, before he became the President, he headed the first company in the United States to build a canal, which was to connect the Ohio and Potomac rivers. It was never completed, but it showed the nation the feasibility of canals. As the country expanded westward, settlers in western New York, Pennsylvania, and Ohio needed a means to ship goods. Canals linking natural waterways seemed to supply an effective method.

  In 1791, engineers commissioned by the state of New York investigated the possibility of a canal between Albany on the Hudson River and Buffalo on Lake Eric to link the Great Lakes area with the Atlantic seacoast. It would avoid the mountains that served as a barrier to canals from the Delaware and Potomac rivers.

  The first attempt to dig the canal, to be called the Eric Canal, was made by private companies but only a comparatively small portion was built before the project was halted for lack of funds. The cost of the prospect was estimated $5 million, an enormous amount for those days. There was some on-again-off-again federal funding, but this time the War of 1812 put an end to construction. In 1817, DeWitt Clinton was elected Governor of New York and persuaded the state to finance and build the canal. It was completed in 1825, costing $2 million more than expected.

  The canal rapidly lived up to its sponsors’ faith, quickly paying for itself through tolls. It was far more economical than any other form of transportation at the time. It permitted trade between the Great Lake region and the East coast, robbing the Mississippi River of much of its traffic. It allowed New York to supplant Boston, Philadelphia, and other eastern cities as the chief center of both domestic and foreign commerce. Cities sprang up along the canal. It also contributed in a number of ways to the North’s victory over the South in the Civil War.

  An expansion of the canal was planned in 1849. Increased traffic would undoubtedly have warranted its construction had it not been for the railroads.

The completion of the Eric Canal was financed by ______.

A. provate company

B. DeWitt Clinton

C. the federal govermment

D. New York

Mark the letter A, B, C or D on your answer sheet to indicate the sentence that is closest in meaning to each of the following questions.

"Why don't you put an advertisement in the local paper?" they told me.

A. They suggested my putting an advertisement in the local paper.

B. They suggested me to put an advertisement in the local paper.

C. They suggested that I must put an advertisement in the local paper.

D. They suggested me should put an advertisement in the local paper.

Mark the letter A, B, C, or D on you answer sheet to indicate the sentence that best combines each pair of sentences in the following questions.

What has happened? You look as if you have been in the wars.

A. You look like an old soldier.

B. You are wearing many medals.

C. You look as though something unpleasant has happened to you.

D. You look as though you have been fighting.

Mark the letter A, B, C, or D on you answer sheet to indicate the sentence that best combines each pair of sentences in the following questions.

He behaved in a very strange way. That surprised me a lot.

A. His behaviour was a very strange thing, that surprised me most.

B. He behaved very strangely, which surprised me very much.

C. What almost surprised me was the strange way he behaved.

D. I was almost not surprised by his strange behaviour.

Tìm x y = 9 11 ; x + y = 60  biết:

Cho tỉ lệ thức  3 x + 5 y x − 2 y = 1 4 . Tính tỉ số  x y