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

Pollution emitted in industrial areas represents a threat to human health and the surrounding natural resources. We have a tendency to believe that the production processes are the only source of environmental damage, and often forget about the possible long-term effects of harmful production practices. We may think that the closure of these huge industrial areas would improve the quality of the environment. Unfortunately, this ignores the threat of the remaining waste, which is abandoned and poorly stored. It represents an even bigger danger because it stands neglected as it degrades and leaks into the earth without any control at all. 

Changes in the water chemistry due to surface water contamination can affect all levels of an ecosystem. It can affect the health of lower food chain organisms and, consequently, the availability of food up through the food chain. It can damage the health of wetlands and damage their ability to support healthy ecosystems, control flooding, and filter pollutants from storm water runoff. The health of animals and humans are affected when they drink or bathe in contaminated water. In addition water-based organisms, like fish and shellfish, can pile up and concentrate contaminants in their bodies. When other animals or humans eat these organisms, they receive a much higher dose of contaminant than they would have if they had been directly exposed to the original contamination. 

Contaminated groundwater can badly affect animals, plants and humans if it is removed from the ground by manmade or natural processes. Depending on the study of rocks of the area, groundwater may rise to the surface through springs or seeps, flow sideways into nearby rivers, streams, or ponds, or sink deeper into the earth. In many parts of fhe world, groundwater is pumped out of the ground to be used for drinking, bathing, other household uses, agriculture, and industry. 

Contaminants in the soil can harm plants when they take up the contamination through their roots. Eating, breathing in, or touching contaminated soil, as well as eating plants or animals that have piled up soil contaminants can badly affect the health of humans and animals. 

Air pollution can cause breathing-related problems and other bad health effects as contaminants are absorbed from the lungs into other parts of the body. Certain air contaminants can also harm animals and humans when they contact the skin. Plants rely on breathing for their growth and can also be affected by exposure to contaminants moved in the air

The word “it” in the first paragraph refers to______.

A. the remaining waste     

B. a danger  

C. the environment  

D. the threat of the remaining waste

Xét dấu tam thức bậc hai: 5x2 - 3x + 1

________rapid population increases and industrial growth, some groups of people have been able to live in harmony with the planet

A. although        

B. In spite   

C. Despite    

D. While

The number of students attending the seminar are smaller than registration numbers.

A. students           

B. attending                   

C. are                             

D. numbers

Mark the letter A, B, C, or D on your answer sheet to indicate the word or phrase that is OPPOSITE  in meaning to the underlined part in each of the followings.

The noise is so faint that it was impossible to be sure what it was or even where it came from

A. general

B. indistinct

C. frightening

D. loud

Cho 2 chất X và Y là đồng phân của nhau đều chứa C, H và 1 nguyên tử oxi, trong phân tử của chúng đều chứa vòng benzen. X có thể tác dụng với Na, NaOH còn Y chỉ tác dụng với Na. Xác định CTCT X, Y biết d X / O 2 = 3 , 375 ?

A. HOC₆H₄CH₃, C₆H₅CH₂OH

B. C₆H₅-O-CH₃,C₆H₅CH₂OH

C. C₆H₅-O-CH₃, HOC₆H₄CH₃

D. Không xác định được

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.

Legend has it that sometime toward the end of the Civil war (1861 – 1865) a government train carrying oxen travelling through the northern plains of eastern Wyoming was caught in a snowstorm and had to be abandoned. The diver returned the next spring to see what had become of his cargo. Instead of the skeletons he had expected to find, he saw his oxen, living, fat and healthy. How had they survived?

The answer lay in the resource that unknowing American lands trampled underfoot in their haste to cross the “Great American Desert” to reach lands that sometimes proved barren. In the eastern parts of the United States, the preferred grass for forage was a cultivated plant. It grew well with enough rain, then when cut and stored it would cure and become nourishing hay for winter feed. But in the dry grazing lands of the west that familiar bluejoint grass was often killed by drought. To cattle out there seemed risky or even hopeless.

Who could imagine a fairy-tail grass that required no rain and somehow made it possible for cattle to feed themselves all winter? But the surprising western wild grasses did just that. They had wonderfully convenient features that made them superior to the cultivated eastern grasses. Variously known as buffalo grass, grama grass, or mesquite grass, not only were they immune to drought; but they were actually preserved by the lack of summer and autumn rains. They were not juicy like the cultivated eastern grasses, but had short, hard stems. And they did not need to be cured in a barn, but dried right where they grew on the ground. When they dried in this way, they remained naturally sweet and nourishing through the winter. Cattle left outdoors to fend for themselves thrived on this hay. And the cattle themselves helped plant the fresh grass year after year for they trampled the natural seeds firmly into the soil to be watered by the melting snows of winter and the occasional rains of spring. The dry summer air cured them much as storing in a barn cured the cultivated grasses.

What can be inferred about the “Great American Desert” mentioned in paragraph 2?

A. Many had settled there by the 1860’s

B. It was not originally assumed to be a fertile area

C. It was a popular place to raise cattle before the Civil War

D. It was not discovered until the late 1800’s

Trong dãy nào sau đây tất cả các muối đều ít tan trong nước?

A. AgI, CuS, BaHPO₄, Ca₃(PO₄)₂

B. AgCl, PbS, Ba(H₂PO₄)₂, Ca(NO₃)₂

C. AgF, CuSO₄, BaCO₃, Ca(H₂PO₄)₂

D. AgNO₃, Na₃PO₄, CaHPO₄, CaSO₄

Cho m gam FeS₂ tác dụng với dung dịch H₂SO₄ đặc, nóng (dư), thu được V lít SO₂ (đktc). Hấp thụ V lít SO₂ này vào 400 ml dung dịch hỗn hợp NaOH 1M và Na₂SO₃ 0,25M, thu đựơc dung dịch Y chứa 2 muối có tỉ lệ số mol n N a H S O 3 : n N a 2 C O 3 = 2 : 1  Giá trị của m là

A. 4,8.

B. 5,6.

C. 21,0.

D. 8,4.