Ve sầu kêu vào mùa hè oi ả, ếch đực kêu vào mùa sinh sản là tập tính:

Một nhóm đoàn viên thanh niên tình nguyện về sinh hoạt tại một xã nông thôn gồm có 21 đoàn viên nam và 15 đoàn viên nữ. Hỏi có bao nhiêu cách phân chia 3 nhóm về 3 ấp để hoạt động sao cho mỗi ấp có 7 đoàn viên nam và 5 đoàn viên nữ?                         

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:

It is hard to think of a world without gas or electricity. Both are commonly used for lighting and heating today. We now can instantly flick a lighter or strike a match to make a flame. But it was not long ago that there were no such things as matches or lighters. To make fire, it was necessary to strike a piece of iron on flint for sparks to ignite some tinder. If the tinder was damp, or the flint old, you had to borrow some fire from a neighbor. We do not know exactly when or how people first used fire. Perhaps, many ages ago, they found that sticks would burn if they were dropped into some hole where melted lava from a volcano lay boiling. They brought the lighted sticks back to make their fire in a cave. Or, they may have seen trees catch fire through being struck by lightning, and used the trees to start their own fires. Gradually people learned they could start a fire without traveling far to find flames. They rubbed two pieces of wood together. This method was used for thousands of years. When people became used to making fires with which to cook food and stay warm at night, they found that certain resins or gums from trees burnt longer and brighter. They melted resins and dipped branches in the liquid to make torches that lit their homes at night. Iron stands in which torches used to be fixed can still be seen in old buildings of Europe. There was no lighting in city streets until gas lamps, and then electric lamps were installed. Boys ran about London at night carrying torches of burning material. They were called torch boys, or link boys, and earned a living by guiding visitors to friends’ houses at night. For centuries homes were lit by candles until oil was found. Even then, oil lamps were no more effective than a cluster of candles. We read about the splendors and marvels of ancient palaces and castles, but we forget that they must have been gloomy and murky places at night.  

Question: It is stated in the passage that torches for lighting were made from ______.         

Tìm biết rằng hệ số của trong khai triển bằng

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:

It is hard to think of a world without gas or electricity. Both are commonly used for lighting and heating today. We now can instantly flick a lighter or strike a match to make a flame. But it was not long ago that there were no such things as matches or lighters. To make fire, it was necessary to strike a piece of iron on flint for sparks to ignite some tinder. If the tinder was damp, or the flint old, you had to borrow some fire from a neighbor. We do not know exactly when or how people first used fire. Perhaps, many ages ago, they found that sticks would burn if they were dropped into some hole where melted lava from a volcano lay boiling. They brought the lighted sticks back to make their fire in a cave. Or, they may have seen trees catch fire through being struck by lightning, and used the trees to start their own fires. Gradually people learned they could start a fire without traveling far to find flames. They rubbed two pieces of wood together. This method was used for thousands of years. When people became used to making fires with which to cook food and stay warm at night, they found that certain resins or gums from trees burnt longer and brighter. They melted resins and dipped branches in the liquid to make torches that lit their homes at night. Iron stands in which torches used to be fixed can still be seen in old buildings of Europe. There was no lighting in city streets until gas lamps, and then electric lamps were installed. Boys ran about London at night carrying torches of burning material. They were called torch boys, or link boys, and earned a living by guiding visitors to friends’ houses at night. For centuries homes were lit by candles until oil was found. Even then, oil lamps were no more effective than a cluster of candles. We read about the splendors and marvels of ancient palaces and castles, but we forget that they must have been gloomy and murky places at night.  

Question: It is mentioned in the passage that before the electric lamp was invented         

Cho biểu thức với , . Tìm số hạng không chứa trong khai triển Niu-tơn của .         

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:

It is hard to think of a world without gas or electricity. Both are commonly used for lighting and heating today. We now can instantly flick a lighter or strike a match to make a flame. But it was not long ago that there were no such things as matches or lighters. To make fire, it was necessary to strike a piece of iron on flint for sparks to ignite some tinder. If the tinder was damp, or the flint old, you had to borrow some fire from a neighbor. We do not know exactly when or how people first used fire. Perhaps, many ages ago, they found that sticks would burn if they were dropped into some hole where melted lava from a volcano lay boiling. They brought the lighted sticks back to make their fire in a cave. Or, they may have seen trees catch fire through being struck by lightning, and used the trees to start their own fires. Gradually people learned they could start a fire without traveling far to find flames. They rubbed two pieces of wood together. This method was used for thousands of years. When people became used to making fires with which to cook food and stay warm at night, they found that certain resins or gums from trees burnt longer and brighter. They melted resins and dipped branches in the liquid to make torches that lit their homes at night. Iron stands in which torches used to be fixed can still be seen in old buildings of Europe. There was no lighting in city streets until gas lamps, and then electric lamps were installed. Boys ran about London at night carrying torches of burning material. They were called torch boys, or link boys, and earned a living by guiding visitors to friends’ houses at night. For centuries homes were lit by candles until oil was found. Even then, oil lamps were no more effective than a cluster of candles. We read about the splendors and marvels of ancient palaces and castles, but we forget that they must have been gloomy and murky places at night.

Question: The word “splendors” in the passage could be best replaced by which of the following?             

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:

Question: It can be inferred from the passage that the author believes that business operated by women are small because ________ .     

Until recently, most American entrepreneurs were men. Discrimination against women in business, the demands of caring for families, and lack of business training had kept the number of women entrepreneurs small. Now, however, businesses owned by women account for more than $40 billion in annual revenues, and this figure is likely to continue rising throughout the 1990s. As Carolyn Doppelt Gray, an official of the Small Business Administration, has noted, "The 1970s was the decade of women entering management, and the 1980s turned out to be the decade of the woman entrepreneur". What are some of the factors behind this trend? For one thing, as more women earn advanced degrees in business and enter the corporate world, they are finding obstacles. Women are still excluded from most executive suites. Charlotte Taylor, a management consultant, had noted, "In the 1970s women believed if they got an MBA and worked hard they could become chairman of the board. Now they've found out that isn't going to happen, so they go out on their own". In the past, most women entrepreneurs worked in "women's" fields: cosmetics and clothing, for example. But this is changing. Consider ASK Computer Systems, a $22-million-a-year computer software business. It was founded in 1973 by Sandra Kurtzig, who was then a housewife with degrees in math and engineering. When Kurtzig founded the business, her first product was software that let weekly newspapers keep tabs on their newspaper carriers-and her office was a bedroom at home, with a shoebox under the bed to hold the company's cash. After she succeeded with the newspaper software system, she hired several bright computer-science graduates to develop additional programs. When these were marketed and sold, ASK began to grow. It now has 200 employees, and Sandra Kurtzig owns $66.9 million of stock. Of course, many women who start their own businesses fail, just as men often do. They still face hurdles in the business world, especially problems in raising money; the banking and finance world is still dominated by men, and old attitudes die hard. Most businesses owned by women are still quite small. But the situation is changing; there are likely to be many more Sandra Kurtzigs in the years ahead.       

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:

Question: The expression “keep tabs on”  is closest meaning to _________ .         

Until recently, most American entrepreneurs were men. Discrimination against women in business, the demands of caring for families, and lack of business training had kept the number of women entrepreneurs small. Now, however, businesses owned by women account for more than $40 billion in annual revenues, and this figure is likely to continue rising throughout the 1990s. As Carolyn Doppelt Gray, an official of the Small Business Administration, has noted, "The 1970s was the decade of women entering management, and the 1980s turned out to be the decade of the woman entrepreneur". What are some of the factors behind this trend? For one thing, as more women earn advanced degrees in business and enter the corporate world, they are finding obstacles. Women are still excluded from most executive suites. Charlotte Taylor, a management consultant, had noted, "In the 1970s women believed if they got an MBA and worked hard they could become chairman of the board. Now they've found out that isn't going to happen, so they go out on their own". In the past, most women entrepreneurs worked in "women's" fields: cosmetics and clothing, for example. But this is changing. Consider ASK Computer Systems, a $22-million-a-year computer software business. It was founded in 1973 by Sandra Kurtzig, who was then a housewife with degrees in math and engineering. When Kurtzig founded the business, her first product was software that let weekly newspapers keep tabs on their newspaper carriers-and her office was a bedroom at home, with a shoebox under the bed to hold the company's cash. After she succeeded with the newspaper software system, she hired several bright computer-science graduates to develop additional programs. When these were marketed and sold, ASK began to grow. It now has 200 employees, and Sandra Kurtzig owns $66.9 million of stock. Of course, many women who start their own businesses fail, just as men often do. They still face hurdles in the business world, especially problems in raising money; the banking and finance world is still dominated by men, and old attitudes die hard. Most businesses owned by women are still quite small. But the situation is changing; there are likely to be many more Sandra Kurtzigs in the years ahead.