Hòa tan hoàn toàn 19,5 gam kim loại kẽm vào dung dịch HCl 1M thấy thoát
ra V lít khí H 2 (đktc)
a. Tính V
b. Tính thể tích dung dịch HCl đã dùng

Cho a,b,c>0 và a+b+c=6

a) \(\frac{a}{b+c}\) + \(\frac{b}{a+c}\) + \(\frac{c}{a+b}\)

Cho điểm M nằm ngoài ( O,R). Kẻ MA là trung tuyến. Kẻ AB ⊥ MO.

a) Chứng minh: MB là tiếp tuyến của ( O )

b) Từ ( O) kẻ đường thẳng Vuông góc OA và cắt MB tại K. Chứng minh: KM=KO

c) MO cắt ( O) tại I ( MI<MO) . CMR: AI là phân giác của MAB

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 1 to 10.

Reading to oneself is a modern activity which was almost unknown to the scholars of the classical and medieval worlds, while during the fifteenth century the term "reading" undoubtedly meant reading aloud. Only during the nineteenth century did silent reading become commonplace.

One should be wary, however, of assuming that silent reading came about simply because reading aloud was a distraction to others. Examinations of factors related to the historical development of silent reading have revealed that it became the usual mode of reading for most adults mainly because the tasks themselves changed in character.

The last century saw a steady gradual increase in literacy and thus in the number of readers. As the number of readers increased, the number of potential listeners declined and thus there was some reduction in the need to read aloud. As reading for the benefit of listeners grew less common, so came the flourishing of reading as a private activity in such public places as libraries, railway carriages and offices, where reading aloud would cause distraction to other readers.

Towards the end of the century, there was still considerable argument over whether books should be used for information or treated respectfully and over whether the reading of materials such as newspapers was in some way mentally weakening. Indeed, this argument remains with us still in education. However, whatever its virtues, the old shared literacy culture had gone and was replaced by the printed mass media on the one hand and by books and periodicals for a specialised readership on the other.

By the end of the twentieth century, students were being recommended to adopt attitudes to books and to use reading skills which were inappropriate, if not impossible, for the oral reader. The social, cultural and technological changes in the century had greatly altered what the term "reading" implied.

Question 1: Reading aloud was more common in the medieval world because:

A. people relied on reading for entertainment

B. silent reading had not been discovered

C. there were few places available for private reading

D. few people could read to themselves

Question 2: The word "commonplace" in the first paragraph mostly means:

A. for everybody's use B. most preferable

C. attracting attention D. widely used

Question 3: The development of silent reading during the last century indicated

A. an increase in the average age of readers

B. an increase in the number of books

C. a change in the nature of reading

D. a change in the status of literate people

Question 4: Silent reading, especially in public places, flourished mainly because of:

A. the decreasing need to read aloud

B. the development of libraries

C. the increase in literacy

D. the decreasing number of listeners

Question 5 It can be inferred that the emergence of the mass media and specialized reading materials was an indication of .

A. a decline of standards of literacy

B. a change in the readers' interest

C. an alteration in educationalists ’attitudes

D. an improvement of printing techniques.

Question 6: The phrase "a specialized readership" in paragraph 4 mostly means:

A. a requirement for readers in a particular area of knowledge

B. a limited number of readers in a particular area of knowledge

C. a reading volume for particular professionals

D. a status for readers specialized in mass media

Question 7: The phrase “oral reader" in the last paragraph mostly means a person who:

A. is good at public speaking

B. practices reading to an audience

C. takes part in an audition

D. is interested in spoken language

Question 8: All of the following might be the factors that affected the continuation of the old shared literacy culture EXCEPT .

A. the inappropriate reading skills B. the specialized readership

C. the diversity of reading materials D. the printed mass media

Question 9: Which of the following statements is NOT TRUE according to the passage?

A. Reading aloud was more common in the past than it is today.

B. Not all printed mass media was appropriate for reading aloud.

C. The decline of reading aloud was wholly due to its distracting effect.

D. The change in reading habits was partly due to the social, cultural and technological changes.

Question 10: The writer of this passage is attempting to .

A. explain how reading habits have developed

B. change people's attitudes to reading

C. show how reading methods have improved

D. encourage the growth of reading.

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 55 to 64.

Overpopulation, the situation of having large numbers of people with too few resources and too little space, is closely associated with poverty. It can result from high population density, or from low amounts of resources, or from both. Excessively high population densities put stress on available resources. Only a certainnumber of people can be supported on a given area of land, and that number depends on how much food and other resources the land can provide. In countries where people live primarily by means of simple farming, gardening, herding, hunting, and gathering, even large areas of land can support only small numbers of people because these labor-intensive subsistence activities produce only small amounts of food.
In developed countries such as the United States, Japan, and the countries of Western Europe, overpopulation generally is not considered a major cause of poverty. These countries produce large quantities of food through mechanized farming, which depends on commercial fertilizers, large-scale irrigation, and agricultural machinery. This form of production provides enough food to support the high densities of people in metropolitan areas.
A country’s level of poverty can depend greatly on its mix of population density and agricultural productivity. Bangladesh, for example, has one of the world’s highest population densities, with 1,147 persons per sq km. A large majority of the people of Bangladesh engage in low-productivity manual farming, which contributes to the country’s extremely high level of poverty. Some of the smaller countries in Western Europe, such as the Netherlands and Belgium, have high population densities as well. These countries practice mechanized farming and are involved in high-tech industries, however, and therefore have high standards of living.
At the other end of the spectrum, many countries in sub-Saharan Africa have population densities of less than 30 persons per sq km. Many people in these countries practice manual subsistence farming; these countries also have infertile land, and lack the economic resources and technology to boost productivity. As a consequence, these nations are very poor. The United States has both relatively low population density and high agricultural productivity; it is one of the world’s wealthiest nations.
High birth rates contribute to overpopulation in many developing countries. Children are assets to many poor families because they provide labor, usually for farming. Cultural norms in traditionally rural societies commonly sanction the value of large families. Also, the governments of developing countries often provide
little or no support, financial or political, for family planning; even people who wish to keep their families small have difficulty doing so. For all these reasons, developing countries tend to have high rates of population growth.

From "Poverty" by Thomas J. Corbett

Which of the following is given a definition in paragraph 1?

Câu 2:

What will suffer when there are excessively high population densities?

Câu 3:

The phrase “that number” in paragraph 1 refers to the number of ______.

Câu 4:

In certain countries, large areas of land can only yield small amounts of food because ______.

Câu 5:

Bangladesh is a country where the level of poverty depends greatly on ______.

Câu 6:

The phrase “engage in” in paragraph 3 is closest in meaning to ______.

Câu 7:

The word “ infertile ” in paragraph 4 probably means ______.

Câu 8:

Which of the following is TRUE, according to the passage?

Câu 9:

Which of the following is a contributor to overpopulation in many developing countries?

Câu 10:

Which of the following could be the best title for the passage?

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 32 to 41.

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 to ward 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.

From "Global Warming" by Michael Mastrandrea an d Stephen H. Schneider

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

Câu 2:

According to paragraph 2, when their habitats grow warmer, animals tend to move ______.

Câu 3:

The pronoun “those” in paragraph 2 refers to ______.

Câu 4:

The phrase “dwindling sea ice” in paragraph 2 refers to ______.

Câu 5:

It is mentioned in the passage that if the global temperature rose by 2 or 3 Celsius degrees, ______.

Câu 6:

According to the passage, if some species are not able to adjust quickly to warmer temperatures, ______.

Câu 7:

The word “fragile” in paragraph 4 most probably means ______.

Câu 8:

The bleaching of coral reefs as mentioned in paragraph 4 indicates ______.

Câu 9:

The level of acidity in the ocean is increased by ______.

Câu 10:

What does the passage mainly discuss?

Cho tam giác ABC, A=90, Sin B=\(\frac{1}{2}\) . Tính B,C