Có con mèo vàng, con mèo đen, con mèo nâu, con mèo trắng , con mèo xanh và con mèo tím. Xếp con mèo thành hàng ngang vào cái ghế, mỗi ghế một con. Hỏi có bao nhiêu cách sắp xếp chỗ sao cho mèo vàng và mèo đen ở cạnh nhau?  

Cho tập , từ tập có thể lập được bao nhiêu số tự nhiên có chữ số và chia hết cho ?  

Có 10 quyển sách Toán, 8 quyển sách Lí, 5 quyển sách Văn. Cần chọn ra 8 quyển có ở cả ba môn sao cho số quyển Toán ít nhất là bốn và số quyển Văn nhiều nhất là hai. Hỏi có bao nhiêu cách chọn?                         

Số có bao nhiêu ước số nguyên?                 

Từ các chữ số 0, 1, 2, 3, 5 có thể lập được bao nhiêu số tự nhiên không chia hết cho 5, gồm 4 chữ số khác nhau?        

Số tập con của một tập hợp gồm phần tử là           

Một trường THPT được cử một học sinh đi dự trại hè toàn quốc. Nhà trường quyết định chọn một học sinh tiên tiến lớp hoặc lớp Hỏi nhà trường có bao nhiêu cách chọn, nếu biết rằng lớp có học sinh tiên tiến và lớp có học sinh tiên tiến?                                 

Trong các phát biểu sau, phát biểu nào dưới đây là đúng?                         

Trong mặt phẳng có đường thẳng song song với nhau và đường thẳng song song khác cùng cắt nhóm đường thẳng đó. Đếm số hình bình hành nhiều nhất được tạo thành có đỉnh là các giao điểm nói trên.        

Từ các chữ số , có thể lập được bao nhiêu số tự nhiên gồm năm chữ số đôi một khác nhau và lớn hơn .  

Có bao nhiêu số tự nhiên có chữ số mà tổng các chữ số trong mỗi số là .

Một tổ có học sinh nữ và học sinh nam. Hỏi có bao nhiêu cách chọn ngẫu nhiên một học sinh của tổ đó đi trực nhật?

Trong một buổi chụp ảnh của trường A, có 5 giáo viên Toán, 3 giáo viên Hóa và 1 giáo viên Vật Lí xếp thành một hàng ngang. Hỏi có bao nhiêu cách xếp để 3 giáo viên Hóa và 1 giáo viên Vật Lí không ai cạnh nhau?                         

Có bao nhiêu số tự nhiên có chữ số sao cho trong mỗi số tổng các chữ số bằng ?         

Một người có cái quần khác nhau, cái áo khác nhau, chiếc cà vạt khác nhau. Để chọn một cái quần hoặc một cái áo hoặc một cái cà vạt thì số cách chọn khác nhau là:                                 

Có con mèo vàng, con mèo đen, con mèo nâu, con mèo trắng , con mèo xanh và con mèo tím. Xếp con mèo thành hàng ngang vào cái ghế, mỗi ghế một con. Hỏi có bao nhiêu cách sắp xếp chỗ sao cho mèo vàng và mèo đen ở cạnh nhau?  

Các thành phố A, B, C, D được nối với nhau bởi các con đường như hình vẽ. Hỏi có bao nhiêu cách đi từ A đến D mà qua B và C chỉ một lần?    

Từ các chữ số 1, 2, 3, 4, 7 có thể lập được bao nhiêu số có ba chữ số khác nhau chia hết cho 2?                         

Có bao nhiêu số có chữ số được tạo thành từ các chữ số , , sao cho bất kì chữ số nào đứng cạnh nhau cũng hơn kém nhau đơn vị?  

Từ chữ số và lập được bao nhiêu số tự nhiên có chữ số sao cho không có chữ số đứng cạnh nhau?         

Số 9779616 có bao nhiêu ước số tự nhiên:  

Cho tập . Hỏi từ B lập được tất cả bao nhiêu số có 5 chữ số khác nhau và chia hết cho 3?                         

Các thành phố A, B, C, D được nối với nhau bởi các con đường như hình vẽ. Hỏi có bao nhiêu cách đi từ A đến D mà qua B và C chỉ một lần?    

Có bao nhiêu số tự nhiên có hai chữ số mà cả hai chữ số đó đều lẻ?  

Cho 6 chữ số 2, 3, 4, 5, 6, 7. Hỏi có bao nhiêu số gồm 3 chữ số được lập thành từ 6 chữ số đó?         

Số có bao nhiêu ước số tự nhiên?                          

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 43 to 50:

Smallpox was the first widespread disease to be eliminated by human intervention. Known as a highly contagious viral disease, it broke out in Europe, causing the deaths of millions of people until the vaccination was invented by Edward Jenner around 1800. In many nations, it was a terror, a fatal disease until very recently. Its victims suffer high fever, vomiting and painful, itchy, pustules that left scars. In villages and cities all over the world, people were worried about suffering smallpox.In May, 1966, the World Health Organization (WHO), an agency of the United Nations was authorized to initiate a global campaign to eradicate smallpox. The goal was to eliminate the disease in one decade. At the time, the disease posed a serious threat to people in more than thirty nations. Because similar projects for malaria and yellow fever had failed, few believed that smallpox could actually be eradicated but eleven years after the initial organization of the campaign, no cases were reported in the field.The strategy was not only to provide mass vaccinations but also to isolate patients with active smallpox in order to contain the spread of the disease and to break the chain of human transmission. Rewards for reporting smallpox assisted in motivating the public to aid health workers. One by one, each small-pox victim was sought out, removed from contact with others and treated. At the same time, the entire village where the victim had lived was vaccinated.By April of 1978 WHO officials announced that they had isolated the last known case of the disease but health workers continued to search for new cases for additional years to be completely sure. In May, 1980, a formal statement was made to the global community. Today smallpox is no longer a threat to humanity. Routine vaccinations have been stopped worldwide.  

Question 49: Which one of the statements doesn’t refer to smallpox?         

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 43 to 50:

Smallpox was the first widespread disease to be eliminated by human intervention. Known as a highly contagious viral disease, it broke out in Europe, causing the deaths of millions of people until the vaccination was invented by Edward Jenner around 1800. In many nations, it was a terror, a fatal disease until very recently. Its victims suffer high fever, vomiting and painful, itchy, pustules that left scars. In villages and cities all over the world, people were worried about suffering smallpox.In May, 1966, the World Health Organization (WHO), an agency of the United Nations was authorized to initiate a global campaign to eradicate smallpox. The goal was to eliminate the disease in one decade. At the time, the disease posed a serious threat to people in more than thirty nations. Because similar projects for malaria and yellow fever had failed, few believed that smallpox could actually be eradicated but eleven years after the initial organization of the campaign, no cases were reported in the field.The strategy was not only to provide mass vaccinations but also to isolate patients with active smallpox in order to contain the spread of the disease and to break the chain of human transmission. Rewards for reporting smallpox assisted in motivating the public to aid health workers. One by one, each small-pox victim was sought out, removed from contact with others and treated. At the same time, the entire village where the victim had lived was vaccinated.By April of 1978 WHO officials announced that they had isolated the last known case of the disease but health workers continued to search for new cases for additional years to be completely sure. In May, 1980, a formal statement was made to the global community. Today smallpox is no longer a threat to humanity. Routine vaccinations have been stopped worldwide.  

Question 50: It can be inferred from the passage 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 from 43 to 50:

Smallpox was the first widespread disease to be eliminated by human intervention. Known as a highly contagious viral disease, it broke out in Europe, causing the deaths of millions of people until the vaccination was invented by Edward Jenner around 1800. In many nations, it was a terror, a fatal disease until very recently. Its victims suffer high fever, vomiting and painful, itchy, pustules that left scars. In villages and cities all over the world, people were worried about suffering smallpox.In May, 1966, the World Health Organization (WHO), an agency of the United Nations was authorized to initiate a global campaign to eradicate smallpox. The goal was to eliminate the disease in one decade. At the time, the disease posed a serious threat to people in more than thirty nations. Because similar projects for malaria and yellow fever had failed, few believed that smallpox could actually be eradicated but eleven years after the initial organization of the campaign, no cases were reported in the field.The strategy was not only to provide mass vaccinations but also to isolate patients with active smallpox in order to contain the spread of the disease and to break the chain of human transmission. Rewards for reporting smallpox assisted in motivating the public to aid health workers. One by one, each small-pox victim was sought out, removed from contact with others and treated. At the same time, the entire village where the victim had lived was vaccinated.By April of 1978 WHO officials announced that they had isolated the last known case of the disease but health workers continued to search for new cases for additional years to be completely sure. In May, 1980, a formal statement was made to the global community. Today smallpox is no longer a threat to humanity. Routine vaccinations have been stopped worldwide.  

Question 47: According to the passage, what way was used to eliminate the spread of smallpox?         

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 43 to 50:

Smallpox was the first widespread disease to be eliminated by human intervention. Known as a highly contagious viral disease, it broke out in Europe, causing the deaths of millions of people until the vaccination was invented by Edward Jenner around 1800. In many nations, it was a terror, a fatal disease until very recently. Its victims suffer high fever, vomiting and painful, itchy, pustules that left scars. In villages and cities all over the world, people were worried about suffering smallpox.In May, 1966, the World Health Organization (WHO), an agency of the United Nations was authorized to initiate a global campaign to eradicate smallpox. The goal was to eliminate the disease in one decade. At the time, the disease posed a serious threat to people in more than thirty nations. Because similar projects for malaria and yellow fever had failed, few believed that smallpox could actually be eradicated but eleven years after the initial organization of the campaign, no cases were reported in the field.The strategy was not only to provide mass vaccinations but also to isolate patients with active smallpox in order to contain the spread of the disease and to break the chain of human transmission. Rewards for reporting smallpox assisted in motivating the public to aid health workers. One by one, each small-pox victim was sought out, removed from contact with others and treated. At the same time, the entire village where the victim had lived was vaccinated.By April of 1978 WHO officials announced that they had isolated the last known case of the disease but health workers continued to search for new cases for additional years to be completely sure. In May, 1980, a formal statement was made to the global community. Today smallpox is no longer a threat to humanity. Routine vaccinations have been stopped worldwide.

Question 48: How was the public motivated to help the health workers?             

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 43 to 50:

Smallpox was the first widespread disease to be eliminated by human intervention. Known as a highly contagious viral disease, it broke out in Europe, causing the deaths of millions of people until the vaccination was invented by Edward Jenner around 1800. In many nations, it was a terror, a fatal disease until very recently. Its victims suffer high fever, vomiting and painful, itchy, pustules that left scars. In villages and cities all over the world, people were worried about suffering smallpox.In May, 1966, the World Health Organization (WHO), an agency of the United Nations was authorized to initiate a global campaign to eradicate smallpox. The goal was to eliminate the disease in one decade. At the time, the disease posed a serious threat to people in more than thirty nations. Because similar projects for malaria and yellow fever had failed, few believed that smallpox could actually be eradicated but eleven years after the initial organization of the campaign, no cases were reported in the field.The strategy was not only to provide mass vaccinations but also to isolate patients with active smallpox in order to contain the spread of the disease and to break the chain of human transmission. Rewards for reporting smallpox assisted in motivating the public to aid health workers. One by one, each small-pox victim was sought out, removed from contact with others and treated. At the same time, the entire village where the victim had lived was vaccinated.By April of 1978 WHO officials announced that they had isolated the last known case of the disease but health workers continued to search for new cases for additional years to be completely sure. In May, 1980, a formal statement was made to the global community. Today smallpox is no longer a threat to humanity. Routine vaccinations have been stopped worldwide.  

 Question 45: The global community considered the smallpox ___________.         

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 43 to 50:

Smallpox was the first widespread disease to be eliminated by human intervention. Known as a highly contagious viral disease, it broke out in Europe, causing the deaths of millions of people until the vaccination was invented by Edward Jenner around 1800. In many nations, it was a terror, a fatal disease until very recently. Its victims suffer high fever, vomiting and painful, itchy, pustules that left scars. In villages and cities all over the world, people were worried about suffering smallpox.In May, 1966, the World Health Organization (WHO), an agency of the United Nations was authorized to initiate a global campaign to eradicate smallpox. The goal was to eliminate the disease in one decade. At the time, the disease posed a serious threat to people in more than thirty nations. Because similar projects for malaria and yellow fever had failed, few believed that smallpox could actually be eradicated but eleven years after the initial organization of the campaign, no cases were reported in the field.The strategy was not only to provide mass vaccinations but also to isolate patients with active smallpox in order to contain the spread of the disease and to break the chain of human transmission. Rewards for reporting smallpox assisted in motivating the public to aid health workers. One by one, each small-pox victim was sought out, removed from contact with others and treated. At the same time, the entire village where the victim had lived was vaccinated.By April of 1978 WHO officials announced that they had isolated the last known case of the disease but health workers continued to search for new cases for additional years to be completely sure. In May, 1980, a formal statement was made to the global community. Today smallpox is no longer a threat to humanity. Routine vaccinations have been stopped worldwide.  

Question 46: The word “threat” in paragraph 2 could best be replaced by ___________.         

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 43 to 50:

Smallpox was the first widespread disease to be eliminated by human intervention. Known as a highly contagious viral disease, it broke out in Europe, causing the deaths of millions of people until the vaccination was invented by Edward Jenner around 1800. In many nations, it was a terror, a fatal disease until very recently. Its victims suffer high fever, vomiting and painful, itchy, pustules that left scars. In villages and cities all over the world, people were worried about suffering smallpox.In May, 1966, the World Health Organization (WHO), an agency of the United Nations was authorized to initiate a global campaign to eradicate smallpox. The goal was to eliminate the disease in one decade. At the time, the disease posed a serious threat to people in more than thirty nations. Because similar projects for malaria and yellow fever had failed, few believed that smallpox could actually be eradicated but eleven years after the initial organization of the campaign, no cases were reported in the field.The strategy was not only to provide mass vaccinations but also to isolate patients with active smallpox in order to contain the spread of the disease and to break the chain of human transmission. Rewards for reporting smallpox assisted in motivating the public to aid health workers. One by one, each small-pox victim was sought out, removed from contact with others and treated. At the same time, the entire village where the victim had lived was vaccinated.By April of 1978 WHO officials announced that they had isolated the last known case of the disease but health workers continued to search for new cases for additional years to be completely sure. In May, 1980, a formal statement was made to the global community. Today smallpox is no longer a threat to humanity. Routine vaccinations have been stopped worldwide.  

Question 43: Which of the following is 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 43 to 50:

Smallpox was the first widespread disease to be eliminated by human intervention. Known as a highly contagious viral disease, it broke out in Europe, causing the deaths of millions of people until the vaccination was invented by Edward Jenner around 1800. In many nations, it was a terror, a fatal disease until very recently. Its victims suffer high fever, vomiting and painful, itchy, pustules that left scars. In villages and cities all over the world, people were worried about suffering smallpox.In May, 1966, the World Health Organization (WHO), an agency of the United Nations was authorized to initiate a global campaign to eradicate smallpox. The goal was to eliminate the disease in one decade. At the time, the disease posed a serious threat to people in more than thirty nations. Because similar projects for malaria and yellow fever had failed, few believed that smallpox could actually be eradicated but eleven years after the initial organization of the campaign, no cases were reported in the field.The strategy was not only to provide mass vaccinations but also to isolate patients with active smallpox in order to contain the spread of the disease and to break the chain of human transmission. Rewards for reporting smallpox assisted in motivating the public to aid health workers. One by one, each small-pox victim was sought out, removed from contact with others and treated. At the same time, the entire village where the victim had lived was vaccinated.By April of 1978 WHO officials announced that they had isolated the last known case of the disease but health workers continued to search for new cases for additional years to be completely sure. In May, 1980, a formal statement was made to the global community. Today smallpox is no longer a threat to humanity. Routine vaccinations have been stopped worldwide.  

 Question 44: The word “contagious” 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 answers:

All mammals feed their young. Beluga whale mothers, for example, nurse their calves for some twenty months, until they are about to give birth again and their young are able to find their own food. The behavior of feeding of the young is built into the reproductive system. It is a nonelective part of parental care and the defining feature of a mammal, the most important thing that mammals - whether marsupials, platypuses, spiny anteaters, or placental mammals - have in common.

For animals other than mammals, then, feeding is not intrinsic to parental care. Animals add it to their reproductive strategies to give them an edge in their lifelong quest for descendants. The most vulnerable moment in any animal's life is when it first finds itself completely on its own, when it must forage and fend for itself. Feeding postpones that moment until a young animal has grown to such a size that it is better able to cope. Young that are fed by their parents become nutritionally independent at a much greater fraction of their full adult size. And in the meantime those young are shielded against the vagaries of fluctuating of difficult-to-find supplies. Once a species does take the step of feeding its young, the young become totally dependent on the extra effort. If both parents are removed, the young generally do not survive.

Question: The word "shielded" in the last paragraph 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 answers:

All mammals feed their young. Beluga whale mothers, for example, nurse their calves for some twenty months, until they are about to give birth again and their young are able to find their own food. The behavior of feeding of the young is built into the reproductive system. It is a nonelective part of parental care and the defining feature of a mammal, the most important thing that mammals - whether marsupials, platypuses, spiny anteaters, or placental mammals - have in common.

For animals other than mammals, then, feeding is not intrinsic to parental care. Animals add it to their reproductive strategies to give them an edge in their lifelong quest for descendants. The most vulnerable moment in any animal's life is when it first finds itself completely on its own, when it must forage and fend for itself. Feeding postpones that moment until a young animal has grown to such a size that it is better able to cope. Young that are fed by their parents become nutritionally independent at a much greater fraction of their full adult size. And in the meantime those young are shielded against the vagaries of fluctuating of difficult-to-find supplies. Once a species does take the step of feeding its young, the young become totally dependent on the extra effort. If both parents are removed, the young generally do not survive.

Question: The word "it" in the third paragraph refers to _______.