Cho m gam tinh bột lên men thành ancol etylic với hiệu suất 81%. Toàn bộ lượng CO2 sinh ra thu được hấp thụ hoàn toàn vào dung dịch Ca(OH)2, thu được 550 gam kết tủa và dung dịch X. Đun kỹ dung dịch X thu thêm được 100 gam kết tủa. Giá trị của m là:  

It is commonly believed in the United States that school is where people go to get an education. Nevertheless, it has been said that today children interrupt their education to go to school .The distinction between schooling and education implied by this remark is important. Education is much more open-ended and all-inclusive than schooling. Education knows no bounds. It can take place anywhere, whether in the shower or on the job, whether in a kitchen or on a tractor. It includes both the formal learning that takes place in schools and the whole universe of informal learning. The agents of education can range from a revered grandparent to the people debating politics on the radio, from a child to a distinguished scientist. Whereas schooling has a certain predictability, education quite often produces surprises. A chance conversation with a stranger may lead a person to discover how little is known of other religions. People are engaged in education from infancy on. Education, then, is a very broad, inclusive term. It is a lifelong process, a process that starts long before the start of school, and one that should be an integral part of one's entire life.  Schooling, on the other hand, is a specific, formalized process, whose general pattern varies little from one setting to the next. Throughout a country, children arrive at school at approximately the same time, take assigned seats, are taught by an adult, use similar textbooks, do homework, take exams, and so on. The slices of reality that are to be learned, whether they are the alphabet or an understanding of the workings of government, have usually been limited by the boundaries of the subject being taught. For example, high school students know that they are not likely to find out in their classes the truth about political problems in their communities or what the newest filmmakers are experimenting with. There are definite conditions surrounding the formalized process of schooling. 

Question 48: The passage supports which of the following conclusions?

It is commonly believed in the United States that school is where people go to get an education. Nevertheless, it has been said that today children interrupt their education to go to school .The distinction between schooling and education implied by this remark is important. Education is much more open-ended and all-inclusive than schooling. Education knows no bounds. It can take place anywhere, whether in the shower or on the job, whether in a kitchen or on a tractor. It includes both the formal learning that takes place in schools and the whole universe of informal learning. The agents of education can range from a revered grandparent to the people debating politics on the radio, from a child to a distinguished scientist. Whereas schooling has a certain predictability, education quite often produces surprises. A chance conversation with a stranger may lead a person to discover how little is known of other religions. People are engaged in education from infancy on. Education, then, is a very broad, inclusive term. It is a lifelong process, a process that starts long before the start of school, and one that should be an integral part of one's entire life.  Schooling, on the other hand, is a specific, formalized process, whose general pattern varies little from one setting to the next. Throughout a country, children arrive at school at approximately the same time, take assigned seats, are taught by an adult, use similar textbooks, do homework, take exams, and so on. The slices of reality that are to be learned, whether they are the alphabet or an understanding of the workings of government, have usually been limited by the boundaries of the subject being taught. For example, high school students know that they are not likely to find out in their classes the truth about political problems in their communities or what the newest filmmakers are experimenting with. There are definite conditions surrounding the formalized process of schooling. 

Question 47: The phrase “For example,” in paragraph 3, introduces a sentence that gives examples of _________.          

It is commonly believed in the United States that school is where people go to get an education. Nevertheless, it has been said that today children interrupt their education to go to school .The distinction between schooling and education implied by this remark is important. Education is much more open-ended and all-inclusive than schooling. Education knows no bounds. It can take place anywhere, whether in the shower or on the job, whether in a kitchen or on a tractor. It includes both the formal learning that takes place in schools and the whole universe of informal learning. The agents of education can range from a revered grandparent to the people debating politics on the radio, from a child to a distinguished scientist. Whereas schooling has a certain predictability, education quite often produces surprises. A chance conversation with a stranger may lead a person to discover how little is known of other religions. People are engaged in education from infancy on. Education, then, is a very broad, inclusive term. It is a lifelong process, a process that starts long before the start of school, and one that should be an integral part of one's entire life.  Schooling, on the other hand, is a specific, formalized process, whose general pattern varies little from one setting to the next. Throughout a country, children arrive at school at approximately the same time, take assigned seats, are taught by an adult, use similar textbooks, do homework, take exams, and so on. The slices of reality that are to be learned, whether they are the alphabet or an understanding of the workings of government, have usually been limited by the boundaries of the subject being taught. For example, high school students know that they are not likely to find out in their classes the truth about political problems in their communities or what the newest filmmakers are experimenting with. There are definite conditions surrounding the formalized process of schooling. 

Question 50: The writer seems to agree that___________.  

It is commonly believed in the United States that school is where people go to get an education. Nevertheless, it has been said that today children interrupt their education to go to school .The distinction between schooling and education implied by this remark is important. Education is much more open-ended and all-inclusive than schooling. Education knows no bounds. It can take place anywhere, whether in the shower or on the job, whether in a kitchen or on a tractor. It includes both the formal learning that takes place in schools and the whole universe of informal learning. The agents of education can range from a revered grandparent to the people debating politics on the radio, from a child to a distinguished scientist. Whereas schooling has a certain predictability, education quite often produces surprises. A chance conversation with a stranger may lead a person to discover how little is known of other religions. People are engaged in education from infancy on. Education, then, is a very broad, inclusive term. It is a lifelong process, a process that starts long before the start of school, and one that should be an integral part of one's entire life.  Schooling, on the other hand, is a specific, formalized process, whose general pattern varies little from one setting to the next. Throughout a country, children arrive at school at approximately the same time, take assigned seats, are taught by an adult, use similar textbooks, do homework, take exams, and so on. The slices of reality that are to be learned, whether they are the alphabet or an understanding of the workings of government, have usually been limited by the boundaries of the subject being taught. For example, high school students know that they are not likely to find out in their classes the truth about political problems in their communities or what the newest filmmakers are experimenting with. There are definite conditions surrounding the formalized process of schooling.

Question 49: The passage is organized by __________.  

Since the dawn of time, people have found ways to communicate with one another. Smoke signals and tribal drums were some of the earliest forms of communication. Letters, carried by birds or by humans on foot or on horseback, made it possible for people to communicate larger amounts of information between two places. The telegram and telephone set the stage for more modern means of communication. With the invention of the cellular phone, communication itself has become mobile. For you, a cell phone is probably just a device that you and your friends use to keep in touch with family and friends, take pictures, play games, or send text message. The definition of a cell phone is more specific: it is a hand-held wireless communication device that sends and receives signals by way of small special areas called cells. Walkie - talkies, telephones and cell phones are duplex communication devices: They make it possible for two people to talk to each other. Cell phones and walkie-talkies are different from regular phones because they can be used in many different locations. A walkie-talkie is sometimes called a half-duplex communication device because only one person can talk at a time. A cell phone is a full-duplex device because it uses both frequencies at the same time. A walkie-talkie has only one channel. A cell phone has more than a thousand channels. A walkie- talkie can transmit and receive signals across a distance of about a mile. A cell phone can transmit and receive signals over hundreds of miles. In 1973, an electronic company called Motorola hired Martin Cooper to work on wireless communication. Motorola and Bell Laboratories (now AT& T) were in a race to invent the first portable communication device. Martin Cooper won the race and became the inventor of the cell phone. On April 3,1973, Cooper made the first cell phone call to his opponent at AT&T while walking down the streets of New York city. People on the sidewalks gazed at Cooper in amazement. Cooper's phone was called A Motorola Dyna-Tac. It weighed a whopping 2.5 pounds (as compared to today's cell phones that weigh as little as 3 or 4 ounces) After the invention of his cell phone, Cooper began thinking of ways to make the cell phone available to the general public. After a decade, Motorola introduced the first cell phone for commercial use. The early cell phone and its service were both expensive. The cell phone itself cost about $3, 500. In 1977, AT&T constructed a cell phone system and tried it out in Chicago with over 2,000 customers. In 1981, a second cellular phone system was started in the Washington, D.C and Baltimore area. It took nearly 37 years for cell phones to become available for general public use. Today, there are more than sixty million cell phone customers with cell phones producing over thirty billion dollars per years. What definition is true of a cell phone?         

Since the dawn of time, people have found ways to communicate with one another. Smoke signals and tribal drums were some of the earliest forms of communication. Letters, carried by birds or by humans on foot or on horseback, made it possible for people to communicate larger amounts of information between two places. The telegram and telephone set the stage for more modern means of communication. With the invention of the cellular phone, communication itself has become mobile. For you, a cell phone is probably just a device that you and your friends use to keep in touch with family and friends, take pictures, play games, or send text message. The definition of a cell phone is more specific: it is a hand-held wireless communication device that sends and receives signals by way of small special areas called cells. Walkie - talkies, telephones and cell phones are duplex communication devices: They make it possible for two people to talk to each other. Cell phones and walkie-talkies are different from regular phones because they can be used in many different locations. A walkie-talkie is sometimes called a half-duplex communication device because only one person can talk at a time. A cell phone is a full-duplex device because it uses both frequencies at the same time. A walkie-talkie has only one channel. A cell phone has more than a thousand channels. A walkie- talkie can transmit and receive signals across a distance of about a mile. A cell phone can transmit and receive signals over hundreds of miles. In 1973, an electronic company called Motorola hired Martin Cooper to work on wireless communication. Motorola and Bell Laboratories (now AT& T) were in a race to invent the first portable communication device. Martin Cooper won the race and became the inventor of the cell phone. On April 3,1973, Cooper made the first cell phone call to his opponent at AT&T while walking down the streets of New York city. People on the sidewalks gazed at Cooper in amazement. Cooper's phone was called A Motorola Dyna-Tac. It weighed a whopping 2.5 pounds (as compared to today's cell phones that weigh as little as 3 or 4 ounces) After the invention of his cell phone, Cooper began thinking of ways to make the cell phone available to the general public. After a decade, Motorola introduced the first cell phone for commercial use. The early cell phone and its service were both expensive. The cell phone itself cost about $3, 500. In 1977, AT&T constructed a cell phone system and tried it out in Chicago with over 2,000 customers. In 1981, a second cellular phone system was started in the Washington, D.C and Baltimore area. It took nearly 37 years for cell phones to become available for general public use. Today, there are more than sixty million cell phone customers with cell phones producing over thirty billion dollars per years. What is the main idea of the passage?         

As heart disease continues to be the number-one killer in the United States, researchers have become increasingly interested in identifying the potential risk factors that trigger heart attacks. High-fat diets and "life in the fast lane" have long been known to contribute to the high incidence of heart failure. But according to new studies, the list of risk factors may be significantly longer and quite surprising. Heart failure, for example, appears to have seasonal and temporal patterns. A higher percentage of heart attacks occur in cold weather, and more people experience heart failure on Monday than on any other day of the week. In addition, people are more susceptible to heart attacks in the first few hours after waking. Cardiologists first observed this morning phenomenon in the mid-1980, and have since discovered a number of possible causes. An early-morning rise in blood pressure, heart rate, and concentration of heart stimulating hormones, plus a reduction of blood flow to the heart, may all contribute to the higher incidence of heart attacks between the hours of 8:00 A.M. and 10:00 A.M. In other studies, both birthdays and bachelorhood have been implicated as risk factors. Statistics reveal that heart attack rates increase significantly for both females and males in the few days immediately preceding and following their birthdays. And unmarried men are more at risk for heart attacks than their married counterparts. Though stress is thought to be linked in some way to all of the aforementioned risk factors, intense research continues in the hope of further comprehending why and how heart failure is triggered. Which of the following does the passage infer?         

As heart disease continues to be the number-one killer in the United States, researchers have become increasingly interested in identifying the potential risk factors that trigger heart attacks. High-fat diets and "life in the fast lane" have long been known to contribute to the high incidence of heart failure. But according to new studies, the list of risk factors may be significantly longer and quite surprising. Heart failure, for example, appears to have seasonal and temporal patterns. A higher percentage of heart attacks occur in cold weather, and more people experience heart failure on Monday than on any other day of the week. In addition, people are more susceptible to heart attacks in the first few hours after waking. Cardiologists first observed this morning phenomenon in the mid-1980, and have since discovered a number of possible causes. An early-morning rise in blood pressure, heart rate, and concentration of heart stimulating hormones, plus a reduction of blood flow to the heart, may all contribute to the higher incidence of heart attacks between the hours of 8:00 A.M. and 10:00 A.M. In other studies, both birthdays and bachelorhood have been implicated as risk factors. Statistics reveal that heart attack rates increase significantly for both females and males in the few days immediately preceding and following their birthdays. And unmarried men are more at risk for heart attacks than their married counterparts. Though stress is thought to be linked in some way to all of the aforementioned risk factors, intense research continues in the hope of further comprehending why and how heart failure is triggered. Which of the following is NOT cited as a possible risk factor?         

Since the dawn of time, people have found ways to communicate with one another. Smoke signals and tribal drums were some of the earliest forms of communication. Letters, carried by birds or by humans on foot or on horseback, made it possible for people to communicate larger amounts of information between two places. The telegram and telephone set the stage for more modern means of communication. With the invention of the cellular phone, communication itself has become mobile. For you, a cell phone is probably just a device that you and your friends use to keep in touch with family and friends, take pictures, play games, or send text message. The definition of a cell phone is more specific: it is a hand-held wireless communication device that sends and receives signals by way of small special areas called cells. Walkie - talkies, telephones and cell phones are duplex communication devices: They make it possible for two people to talk to each other. Cell phones and walkie-talkies are different from regular phones because they can be used in many different locations. A walkie-talkie is sometimes called a half-duplex communication device because only one person can talk at a time. A cell phone is a full-duplex device because it uses both frequencies at the same time. A walkie-talkie has only one channel. A cell phone has more than a thousand channels. A walkie- talkie can transmit and receive signals across a distance of about a mile. A cell phone can transmit and receive signals over hundreds of miles. In 1973, an electronic company called Motorola hired Martin Cooper to work on wireless communication. Motorola and Bell Laboratories (now AT& T) were in a race to invent the first portable communication device. Martin Cooper won the race and became the inventor of the cell phone. On April 3,1973, Cooper made the first cell phone call to his opponent at AT&T while walking down the streets of New York city. People on the sidewalks gazed at Cooper in amazement. Cooper's phone was called A Motorola Dyna-Tac. It weighed a whopping 2.5 pounds (as compared to today's cell phones that weigh as little as 3 or 4 ounces) After the invention of his cell phone, Cooper began thinking of ways to make the cell phone available to the general public. After a decade, Motorola introduced the first cell phone for commercial use. The early cell phone and its service were both expensive. The cell phone itself cost about $3, 500. In 1977, AT&T constructed a cell phone system and tried it out in Chicago with over 2,000 customers. In 1981, a second cellular phone system was started in the Washington, D.C and Baltimore area. It took nearly 37 years for cell phones to become available for general public use. Today, there are more than sixty million cell phone customers with cell phones producing over thirty billion dollars per years.   When did AT&T widely start their cellular phone system?  

Since the dawn of time, people have found ways to communicate with one another. Smoke signals and tribal drums were some of the earliest forms of communication. Letters, carried by birds or by humans on foot or on horseback, made it possible for people to communicate larger amounts of information between two places. The telegram and telephone set the stage for more modern means of communication. With the invention of the cellular phone, communication itself has become mobile. For you, a cell phone is probably just a device that you and your friends use to keep in touch with family and friends, take pictures, play games, or send text message. The definition of a cell phone is more specific: it is a hand-held wireless communication device that sends and receives signals by way of small special areas called cells. Walkie - talkies, telephones and cell phones are duplex communication devices: They make it possible for two people to talk to each other. Cell phones and walkie-talkies are different from regular phones because they can be used in many different locations. A walkie-talkie is sometimes called a half-duplex communication device because only one person can talk at a time. A cell phone is a full-duplex device because it uses both frequencies at the same time. A walkie-talkie has only one channel. A cell phone has more than a thousand channels. A walkie- talkie can transmit and receive signals across a distance of about a mile. A cell phone can transmit and receive signals over hundreds of miles. In 1973, an electronic company called Motorola hired Martin Cooper to work on wireless communication. Motorola and Bell Laboratories (now AT& T) were in a race to invent the first portable communication device. Martin Cooper won the race and became the inventor of the cell phone. On April 3,1973, Cooper made the first cell phone call to his opponent at AT&T while walking down the streets of New York city. People on the sidewalks gazed at Cooper in amazement. Cooper's phone was called A Motorola Dyna-Tac. It weighed a whopping 2.5 pounds (as compared to today's cell phones that weigh as little as 3 or 4 ounces) After the invention of his cell phone, Cooper began thinking of ways to make the cell phone available to the general public. After a decade, Motorola introduced the first cell phone for commercial use. The early cell phone and its service were both expensive. The cell phone itself cost about $3, 500. In 1977, AT&T constructed a cell phone system and tried it out in Chicago with over 2,000 customers. In 1981, a second cellular phone system was started in the Washington, D.C and Baltimore area. It took nearly 37 years for cell phones to become available for general public use. Today, there are more than sixty million cell phone customers with cell phones producing over thirty billion dollars per years. How heavy is the first cell phone compared to today's cell phones?