Cho tứ diện S.ABC có đáy ABC là tam giác vuông tại B với AB = 3a, BC = 4a, SA, cạnh bên SC tạo với đáy góc 60^o. Khi đó thể tích khối cầu ngoại tiếp S.ABC là:

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:

A survey is a study, generally in the form of an interview or a ques­tionnaire, which provides information concerning how people think and act. In the United States, the best-known surveys are the Gallup poll and the Harris poll. As anyone who watches the news during presiden­tial campaigns knows, these polls have become an important part of political life in the United States.

North Americans are familiar with the many "person on the street" interviews on local television news shows. While such interviews can be highly entertaining, they are not necessarily an accurate indication of public opinion. First, they reflect the opinions of only those people who appear at a certain location. Thus, such samples can be biased in favor of commuters, middle-class shoppers, or factory workers, depending on which area the new people select. Second, television interviews tend to attract outgoing people who are willing to appear on the air, while they frighten away others who may feel intimidated by a camera. A survey must be based on a precise, representative sampling if it is to genu­inely reflect a broad range of the population.

In preparing to conduct a survey, sociologists must exercisegreat care in the wording of questions. An effective survey question must be simple and clear enough for people to understand it. It must also be specific enough so that there are no problems in interpreting the re­sults. Even questions that are less structured must be carefully phrased in order to elicitthe type of information desired. Surveys can be indispensable sources of information, but only if the sampling is done properly and the questions are worded accurately.

There are two main forms of surveys: the interview and the ques­tionnaire. Each of these forms of survey research has its advantages. An interviewer can obtain a high response rate because people find it more difficult to turn down a personal request for an interview than to throw away a written questionnaire. In addition, an interviewer can go beyond written questions and probefor a subject's underlying feelings and reasons. However, questionnaires have the advantage of being cheaper and more consistent.

Question 40: According to the passage, the main disadvantage of person-on-the-street interviews is that they______          

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:

A survey is a study, generally in the form of an interview or a ques­tionnaire, which provides information concerning how people think and act. In the United States, the best-known surveys are the Gallup poll and the Harris poll. As anyone who watches the news during presiden­tial campaigns knows, these polls have become an important part of political life in the United States.

North Americans are familiar with the many "person on the street" interviews on local television news shows. While such interviews can be highly entertaining, they are not necessarily an accurate indication of public opinion. First, they reflect the opinions of only those people who appear at a certain location. Thus, such samples can be biased in favor of commuters, middle-class shoppers, or factory workers, depending on which area the new people select. Second, television interviews tend to attract outgoing people who are willing to appear on the air, while they frighten away others who may feel intimidated by a camera. A survey must be based on a precise, representative sampling if it is to genu­inely reflect a broad range of the population.

In preparing to conduct a survey, sociologists must exercisegreat care in the wording of questions. An effective survey question must be simple and clear enough for people to understand it. It must also be specific enough so that there are no problems in interpreting the re­sults. Even questions that are less structured must be carefully phrased in order to elicitthe type of information desired. Surveys can be indispensable sources of information, but only if the sampling is done properly and the questions are worded accurately.

There are two main forms of surveys: the interview and the ques­tionnaire. Each of these forms of survey research has its advantages. An interviewer can obtain a high response rate because people find it more difficult to turn down a personal request for an interview than to throw away a written questionnaire. In addition, an interviewer can go beyond written questions and probefor a subject's underlying feelings and reasons. However, questionnaires have the advantage of being cheaper and more consistent.

Question 41: It can be inferred from the passage that one reason that sociologists may become frustrated with questionnaires is that______           

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:

A survey is a study, generally in the form of an interview or a ques­tionnaire, which provides information concerning how people think and act. In the United States, the best-known surveys are the Gallup poll and the Harris poll. As anyone who watches the news during presiden­tial campaigns knows, these polls have become an important part of political life in the United States.

North Americans are familiar with the many "person on the street" interviews on local television news shows. While such interviews can be highly entertaining, they are not necessarily an accurate indication of public opinion. First, they reflect the opinions of only those people who appear at a certain location. Thus, such samples can be biased in favor of commuters, middle-class shoppers, or factory workers, depending on which area the new people select. Second, television interviews tend to attract outgoing people who are willing to appear on the air, while they frighten away others who may feel intimidated by a camera. A survey must be based on a precise, representative sampling if it is to genu­inely reflect a broad range of the population.

In preparing to conduct a survey, sociologists must exercisegreat care in the wording of questions. An effective survey question must be simple and clear enough for people to understand it. It must also be specific enough so that there are no problems in interpreting the re­sults. Even questions that are less structured must be carefully phrased in order to elicitthe type of information desired. Surveys can be indispensable sources of information, but only if the sampling is done properly and the questions are worded accurately.

There are two main forms of surveys: the interview and the ques­tionnaire. Each of these forms of survey research has its advantages. An interviewer can obtain a high response rate because people find it more difficult to turn down a personal request for an interview than to throw away a written questionnaire. In addition, an interviewer can go beyond written questions and probefor a subject's underlying feelings and reasons. However, questionnaires have the advantage of being cheaper and more consistent.

Question 42: According to paragraph 3, which of the following is most important for an effective survey?  

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:

A survey is a study, generally in the form of an interview or a ques­tionnaire, which provides information concerning how people think and act. In the United States, the best-known surveys are the Gallup poll and the Harris poll. As anyone who watches the news during presiden­tial campaigns knows, these polls have become an important part of political life in the United States.

North Americans are familiar with the many "person on the street" interviews on local television news shows. While such interviews can be highly entertaining, they are not necessarily an accurate indication of public opinion. First, they reflect the opinions of only those people who appear at a certain location. Thus, such samples can be biased in favor of commuters, middle-class shoppers, or factory workers, depending on which area the new people select. Second, television interviews tend to attract outgoing people who are willing to appear on the air, while they frighten away others who may feel intimidated by a camera. A survey must be based on a precise, representative sampling if it is to genu­inely reflect a broad range of the population.

In preparing to conduct a survey, sociologists must exercisegreat care in the wording of questions. An effective survey question must be simple and clear enough for people to understand it. It must also be specific enough so that there are no problems in interpreting the re­sults. Even questions that are less structured must be carefully phrased in order to elicitthe type of information desired. Surveys can be indispensable sources of information, but only if the sampling is done properly and the questions are worded accurately.

There are two main forms of surveys: the interview and the ques­tionnaire. Each of these forms of survey research has its advantages. An interviewer can obtain a high response rate because people find it more difficult to turn down a personal request for an interview than to throw away a written questionnaire. In addition, an interviewer can go beyond written questions and probefor a subject's underlying feelings and reasons. However, questionnaires have the advantage of being cheaper and more consistent.

Question 43: The word "elicit" in line 18 is closest in meaning to _______         

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:

Are organically grown foods the best choices? The advantage claimed for such foods over conventionally grown and marketed food products are now being debated. Advocates of organic foods - a term whose meaning varies greatly - frequently proclaim that such products are safer and more nutritious than others. The growing interest of consumers in the safety and nutritional quality of the typical North American diet is a welcome development. However, much of this interest has been sparked by sweeping claims that the food supply is unsafe or inadequate in meeting nutritional evidence, the preponderance of written material advancing. As a result, claims that eating a diet consisting of entirely organically grown foods prevents or cures diseases provides other benefits to health have become widely publicized and form the basis for folklore. Almost daily, the public is besieged by claims for “no - aging” diets, new vitamins, and other wonder foods. There are numerous unsubstantiated reports that natural to unfertilized eggs, that untreated grains are better than fumigated grains, and the like. One thing that most organically grown food products seem to have in common is that they cost more than conventionally grown foods. But in many cases, consumers misled if they believe organic foods can maintain health and provide better nutritional quality than conventionally grown foods. So there is real cause for concern if consumers particularly those with limited incomes, distrust the regular food supply and buy only expensive organic foods instead.

Question 45: The phrase “besieged by claims” in paragraph 3 can be understood as ______.         

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:

Are organically grown foods the best choices? The advantage claimed for such foods over conventionally grown and marketed food products are now being debated. Advocates of organic foods - a term whose meaning varies greatly - frequently proclaim that such products are safer and more nutritious than others. The growing interest of consumers in the safety and nutritional quality of the typical North American diet is a welcome development. However, much of this interest has been sparked by sweeping claims that the food supply is unsafe or inadequate in meeting nutritional evidence, the preponderance of written material advancing. As a result, claims that eating a diet consisting of entirely organically grown foods prevents or cures diseases provides other benefits to health have become widely publicized and form the basis for folklore. Almost daily, the public is besieged by claims for “no - aging” diets, new vitamins, and other wonder foods. There are numerous unsubstantiated reports that natural to unfertilized eggs, that untreated grains are better than fumigated grains, and the like. One thing that most organically grown food products seem to have in common is that they cost more than conventionally grown foods. But in many cases, consumers misled if they believe organic foods can maintain health and provide better nutritional quality than conventionally grown foods. So there is real cause for concern if consumers particularly those with limited incomes, distrust the regular food supply and buy only expensive organic foods instead.

Question 44: The “welcome development” mentioned in paragraph 2 is an increase in ____.         

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:

Computers have led to a greater change in our society in recent decades than any other force and are likely to continue to do so until the next century. The industry surrounding computers is growing quickly, providing employment for many but meanwhile making others redundant. Jobs that computers can do much more reliably, faster and cheaper are lost. The redeployment of labour and the prospect of increased leisure are causing social upheavals which require new ideas and significant changes of attitude.

Question 41: As implied in the passage, the widespread use of computers in industry _______.         

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:

Computers have led to a greater change in our society in recent decades than any other force and are likely to continue to do so until the next century. The industry surrounding computers is growing quickly, providing employment for many but meanwhile making others redundant. Jobs that computers can do much more reliably, faster and cheaper are lost. The redeployment of labour and the prospect of increased leisure are causing social upheavals which require new ideas and significant changes of attitude.

Question 40: According to the passage, the impact computers have had on society ___________.         

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:

Are organically grown foods the best choices? The advantage claimed for such foods over conventionally grown and marketed food products are now being debated. Advocates of organic foods - a term whose meaning varies greatly - frequently proclaim that such products are safer and more nutritious than others. The growing interest of consumers in the safety and nutritional quality of the typical North American diet is a welcome development. However, much of this interest has been sparked by sweeping claims that the food supply is unsafe or inadequate in meeting nutritional evidence, the preponderance of written material advancing. As a result, claims that eating a diet consisting of entirely organically grown foods prevents or cures diseases provides other benefits to health have become widely publicized and form the basis for folklore. Almost daily, the public is besieged by claims for “no - aging” diets, new vitamins, and other wonder foods. There are numerous unsubstantiated reports that natural to unfertilized eggs, that untreated grains are better than fumigated grains, and the like. One thing that most organically grown food products seem to have in common is that they cost more than conventionally grown foods. But in many cases, consumers misled if they believe organic foods can maintain health and provide better nutritional quality than conventionally grown foods. So there is real cause for concern if consumers particularly those with limited incomes, distrust the regular food supply and buy only expensive organic foods instead.

Question 43: The word “others” in paragraph 1 refers to _________.         

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:

Are organically grown foods the best choices? The advantage claimed for such foods over conventionally grown and marketed food products are now being debated. Advocates of organic foods - a term whose meaning varies greatly - frequently proclaim that such products are safer and more nutritious than others. The growing interest of consumers in the safety and nutritional quality of the typical North American diet is a welcome development. However, much of this interest has been sparked by sweeping claims that the food supply is unsafe or inadequate in meeting nutritional evidence, the preponderance of written material advancing. As a result, claims that eating a diet consisting of entirely organically grown foods prevents or cures diseases provides other benefits to health have become widely publicized and form the basis for folklore. Almost daily, the public is besieged by claims for “no - aging” diets, new vitamins, and other wonder foods. There are numerous unsubstantiated reports that natural to unfertilized eggs, that untreated grains are better than fumigated grains, and the like. One thing that most organically grown food products seem to have in common is that they cost more than conventionally grown foods. But in many cases, consumers misled if they believe organic foods can maintain health and provide better nutritional quality than conventionally grown foods. So there is real cause for concern if consumers particularly those with limited incomes, distrust the regular food supply and buy only expensive organic foods instead.

Question 42: The word “advocates” in paragraph 1 is closest in meaning to which of the following?