Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions from 8 to 19.

______ of the financial crisis, all they could do was hold on and hope that things would improve.

A. On the top

B. At the height

C. In the end

D. At the bottom

Thí nghiệm 1: Điều chế FeCl2.

Kim loại Al không phản ứng với chất nào sau đây trong dung dịch?

A. Fe₂(SO₄)₃.

B. CuSO₄.

C. HCl.

D. MgCl₂.

Cho 500 ml dung dịch glucozơ phản ứng hoàn toàn với lượng dư dung dịch AgNO₃ trong NH₃ (đun nóng), thu được 10,8 gam Ag. Nồng độ mol của dung dịch glucozơ đã dùng là

A. 0,20M

B. 0,01M

C. 0,02M

D. 0,10M

Read the following passage and blacken the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following questions.

In the American colonies there was little money. England did not supply the colonies with coins and did not allow the colonies to make their own coins, except for the Massachusetts Bay Colony, which received permission for a short period in 1652 to make several kinds of silver coins. England wanted to keep money out of America as a means of controlling trade: America was forced to trade only with England if it did not have the money to buy products from other countries. The result during this pre-revolutionary period was that the colonists used various goods in place of money: beaver pelts, Indian wampum, and tobacco leaves were all commonly used substitutes for money. The colonists also made use of any foreign coins they could obtain. Dutch, Spanish, French, and English coins were all in use in the American colonies.

During the Revolutionary War, funds were needed to finance the world, so each of the individual states and the Continental Congress issued paper money. So much of this paper money was printed that by the end of the war, almost no one would accept it. As a result, trade in goods and the use of foreign coins still flourished during this period.

By the time the Revolutionary War had been won by the American colonists, the monetary system was in a state of total disarray. To remedy this situation, the new Constitution of the United States, approved in 1789, allowed Congress to issue money. The individual States could no longer have their own money supply. A few years later, the Coinage Act of 1792 made the dollar the official currency of the United States and put the country on a bimetallic standard. In this bimetallic system, both gold and silver were legal money, and the rate of exchange of silver to gold was fixed by the government at sixteen to one

The pronoun “it” in paragraph 2 refers to which of the following

A. The Continental Congress

B. Trade in goods

C. The War

D. Paper money

Sơ đồ nào sau đây mô tả đúng về một chuỗi thức ăn?

A. Lúa → rắn → chuột → diều hâu

B. Lúa → chuột → diều hâu → rắn

C. Lúa → chuột → rắn → diều hâu  

D. Lúa → diều hâu → chuột → rắn

Kết quả thí nghiệm của các dung dịch X, Y, Z, T với thuốc thử được ghi ở bằng sau:

Các dung dịch X, Y, Z, T lần lượt là

A. Axit glutamic, tinh bột, phenol, glucozơ.                          

B. Axit glutamic, tinh bột, fructozơ, phenol.

C. Axit glutamic, fructozơ, tinh bột, phenol.        

D. Anilin, tinh bột, fructozơ, axit glutamic.

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.

        The main cause of tooth decay is acid, which is produced by bacteria in the mouth. The acid removes minerals from tooth enamel, allowing tooth decay to begin; the saliva in your mouth encourages remineralization and neutralizes the acid. The rate at which bacteria in the mouth produce acid depends on the amount of plaque on the teeth, the composition of the microbial flora, and whether the bacteria of the plaque have been “primed” by frequent exposure to sugar. To keep your teeth healthy, a regular dental hygiene program should be followed.

        Removing plaque with a toothbrush and dental floss temporarily reduces the numbers of bacteria in the mouth and thus reduces tooth decay. It also makes the surfaces of the teeth more accessible, enabling saliva to neutralize acid and remineralize lesions. If fluoride is present in drinking water when teeth are forming, some fluoride is incorporated into the enamel of the teeth, making them more resistant to attack by acid. Fluoride toothpaste seems to act in another way, by promoting the remineralization of early carious lesions.

                   In addition to a regular dental hygiene program, a good way to keep your teeth healthy is to reduce your intake of sweet food. The least cavity-causing way to eat sweets is to have them with meals and not between. The number of times you eat sweets rather than the total amount determines how much harmful acid the bacteria in your saliva produce. But the amount of sweets influences the quality of your saliva. Avoid, if you can, sticky sweets that stay in your mouth a long time. Also try to brush and floss your teeth after eating sugary foods. Even rinsing your mouth with water is effective. Whenever possible, eat foods with fiber, such as raw carrot sticks, apples, celery sticks, etc., that scrape off plaque, acting as a toothbrush. Cavities can be greatly reduced if these rules are followed when eating sweets.

What can be concluded from the passage about sweets?

A. All sweets should be avoided.

B. Sweets should be eaten with care.

C. It is better to eat sweets a little at a time throughout the day.

D. Sticky sweets are less harmful than other sweets.

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.

        Glass is a remarkable substance made from the simplest raw materials. It can be colored or colorless, monochrome or polychrome, transparent, translucent, or opaque. It is lightweight impermeable to liquids, readily cleaned and reused, durable yet fragile, and often very beautiful Glass can be decorated in multiple ways and its optical properties are exceptional. In all its myriad forms - as table ware, containers, in architecture and design - glass represents a major achievement in the history of technological developments.

        Since the Bronze Age about 3,000 B.C., glass has been used for making various kinds of objects. It was first made from a mixture of silica, line and an alkali such as soda or potash, and these remained the basic ingredients of glass until the development of lead glass in the seventeenth century. When heated, the mixture becomes soft and malleable and can be formed by various techniques into a vast array of shapes and sizes. The homogeneous mass thus formed by melting then cools to create glass, but in contrast to most materials formed in this way (metals, for instance), glass lacks the crystalline structure normally associated with solids, and instead retains the random molecular structure of a liquid. In effect, as molten glass cools, it progressively stiffens until rigid, but does so without setting up a network of interlocking crystals customarily associated with that process. This is why glass shatters so easily when dealt a blow. Why glass deteriorates over time, especially when exposed to moisture, and why glassware must be slowly reheated and uniformly cooled after manufacture to release internal stresses induced by uneven cooling.

        Another unusual feature of glass is the manner in which its viscosity changes as it turns from a cold substance into a hot, ductile liquid. Unlike metals that flow or “freeze” at specific temperatures glass progressively softens as the temperature rises, going through varying stages of malleability until it flows like a thick syrup. Each stage of malleability allows the glass to be manipulated into various forms, by different techniques, and if suddenly cooled the object retains the shape achieved at that point. Glass is thus amenable to a greater number of heat-forming techniques than most other materials.

The words “exposed to” in paragraph 2 most likely mean _________.

A. hardened by

B. chilled with

C. subjected to

D. deprived of

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.

        Glass is a remarkable substance made from the simplest raw materials. It can be colored or colorless, monochrome or polychrome, transparent, translucent, or opaque. It is lightweight impermeable to liquids, readily cleaned and reused, durable yet fragile, and often very beautiful Glass can be decorated in multiple ways and its optical properties are exceptional. In all its myriad forms - as table ware, containers, in architecture and design - glass represents a major achievement in the history of technological developments.

        Since the Bronze Age about 3,000 B.C., glass has been used for making various kinds of objects. It was first made from a mixture of silica, line and an alkali such as soda or potash, and these remained the basic ingredients of glass until the development of lead glass in the seventeenth century. When heated, the mixture becomes soft and malleable and can be formed by various techniques into a vast array of shapes and sizes. The homogeneous mass thus formed by melting then cools to create glass, but in contrast to most materials formed in this way (metals, for instance), glass lacks the crystalline structure normally associated with solids, and instead retains the random molecular structure of a liquid. In effect, as molten glass cools, it progressively stiffens until rigid, but does so without setting up a network of interlocking crystals customarily associated with that process. This is why glass shatters so easily when dealt a blow. Why glass deteriorates over time, especially when exposed to moisture, and why glassware must be slowly reheated and uniformly cooled after manufacture to release internal stresses induced by uneven cooling.

        Another unusual feature of glass is the manner in which its viscosity changes as it turns from a cold substance into a hot, ductile liquid. Unlike metals that flow or “freeze” at specific temperatures glass progressively softens as the temperature rises, going through varying stages of malleability until it flows like a thick syrup. Each stage of malleability allows the glass to be manipulated into various forms, by different techniques, and if suddenly cooled the object retains the shape achieved at that point. Glass is thus amenable to a greater number of heat-forming techniques than most other materials.

Why does the author list the characteristics of glass in paragraph 1?

A. To demonstrate how glass evolved 

B. To show the versatility of glass 

C. To explain glassmaking technology 

D. To explain the purpose of each component of glass