Cho phương trình (S): x² + my² + z² + 2(m - 1)x - 2y + 2z - m + 3 = 0
Với giá trị nào của m, phương trình đã cho là phương trình của mặt cầu?

Tập hợp các điểm cách đều hai mặt phẳng song song là:

Trong không gian Oxyz cho các điểm A(3 ; 0 ; 0), B(0, 4, 0), C(0 ; 0 ; 6). Giá trị gần đúng đến đơn vị giây của góc hợp bởi mặt phẳng (Oxy) và mặt phẳng (ABC) là:

Cho hình chóp S.ABCD có đáy ABCD là hình vuông tâm O cạnh bằng 1, SO vuông góc với mặt phẳng (ABCD) tại O và SO = 1. Khi đó, góc giữa hai mặt phẳng (SAC) và (SBD) bằng:

Giao điểm của mặt cầu (S): (x + 1)² + (y - 2)² + (z - 1)² = 4 và đường thẳng có tọa độ là:

Cho đường thẳng  và mặt phẳng(α): x + y + z - 1 = 0. Vị trí tương đối của d và (α) là:

Cho điểm A (1 ; -1 ; 0) và đường thẳng . Khoảng cách từ A đến d bằng:

Cho phương trình (S): x² + my² + z² + 2(m - 1)x - 2y + 2z - m + 3 = 0
Với giá trị nào của m, phương trình đã cho là phương trình của mặt cầu?

Trong các phương trình sau, phương trình nào là phương trình của mặt cầu?

Trong không gian Oxỵz cho mặt phẳng (α): Ax + By + Cz + D = 0. Mệnh đề nào sau đây đúng?

Điểm nào sau đây cách đều hai mặt phẳng Oyz và Oxz:

Cho đường thẳng  đi qua điểm M₀(x₀ ; y₀ ; z₀), có vectơ chỉ phương  = (a ; b ; c) và mặt phẳng (α): Ax + By + Cz + D = 0 có vectơ pháp tuyến  = (A ; B ;C ). Mệnh đề nào sau đây đúng?

Cho d là đường thẳng đi qua hai điểm A(2 ; -1 ; 3) và B(0 ; 2 ; 1). Phương trình nào sau đây là phương trình tham số của d?

Cho đường thẳng  và mặt phẳng(α): x - y - 2z + 1 = 0. Vị trí tương đối của d và (α) là:

Cho các điểm A(0 ; 0 ; 2), B(1 ; 0 ; 0), C(2 ; 2 ; 0), D(0 ; m ; 0). Điều kiện cần và đủ của m để khoảng cách giữa hai đường thẳng AB và CD bằng 2 là:

Gọi M₁, M₂, M₃ lần lượt là hình chiếu của điểm M (-1 ; 2 ; 5) trên các trục Ox, Oy, Oz. Khi đó phương trình mặt phẳng (M₁M₂M₃) là:

Cho măt cầu (S) : x² + y² + z² = 9 và đường thẳng . Với giá trị nào sau đây của m thì d là tiếp tuyến của (S)?

Đường thẳng nào sau đây nằm trong mặt phẳng (P) : 3x - 6y - 2z - 3 = 0?

Cho ba điểm M(1 ; 0 ; 0), N(0 ; 1 ; 0), P(0 ; 0 ; 1), cosin của góc giữa mặt phẳng (MNP) và mặt phẳng (Oxy) bằng:

Để viết phương trình đường vuông góc chung của hai đường thẳng chéo nhau a và b, một học sinh đã làm như sau:

Bước 1: Viết phương trình mặt phẳng (Q) chứa b và song song với a.

Bước 2: Viết phương trình hình chiếu a' của a trên mặt phẳng (Q).

Bước 3: Tìm giao điểm M của a' và b.

Bước 4: Viết phương trình đường thẳng d qua M và vuông góc với (Q).

Kết luận d là đường vuông góc chung của a và b.

Hỏi cách giải trên đúng hay sai, nếu sai, sai từ bước nào?

Mặt cầu nào sau đây có tâm nằm trên mặt phẳng tọa độ Oxy?

Read the following pasage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 31 to 35:

Our classes take place for three hours every morning from Monday to Friday. The (31)_________ class size is twelve and the average is ten. We use modern methods (32)_________ teaching  and learning, and the school has a language laboratory, a video camera and recorders. You will only be successful in improving your English; however, if you work hard and practise speaking English as much as you can. You will take a short (33)_________ in English as soon as you arrive. In this way, we can put you in a (34)_________ at the most suitable level. The emphasis is on oral communication practice in a wide (35)_________ of situations at the advanced knowledge. You will learn how to use language correctly and appropriately when you talk to native speakers. In addition, you will develop such study skills as reading efficiently, writing articles and reports, and note-taking from books and lectures.  

Question 35:         

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 31 to 35:

Some years ago, my daughter was studying English at a university on the south coast. One evening she phoned to tell me that what she really wanted to do was looking (31) ________the world, so she was looking into the possibility of working in another country. She had seen several (32) ________ in the newspaper for student teachers of English abroad, and she was interested in one in Italy, which she was desperate to visit. She decided that this would be a good way to achieve her ambition, so she was writing to apply for the job. The reply took a long time to arrive, but eventually she received a letter asking if she would go for an interview in London the following week. She was so excited that she immediately got in touch with the school owner and agreed to attend the interview. She was determined that nothing would prevent her (33) ________ doing what she had set out to do. A few days before the interview she had a very strange dream in which she gave birth to a beautiful baby. She was a little nervous and (34) ________about the dream and phoned to ask me what I thought it might mean. As I knew something about dreams, I was able to assure her that it only symbolized her (35) ________to do well in the interview. 

Question 35:

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 31 to 35:

Some years ago, my daughter was studying English at a university on the south coast. One evening she phoned to tell me that what she really wanted to do was looking (31) ________the world, so she was looking into the possibility of working in another country. She had seen several (32) ________ in the newspaper for student teachers of English abroad, and she was interested in one in Italy, which she was desperate to visit. She decided that this would be a good way to achieve her ambition, so she was writing to apply for the job. The reply took a long time to arrive, but eventually she received a letter asking if she would go for an interview in London the following week. She was so excited that she immediately got in touch with the school owner and agreed to attend the interview. She was determined that nothing would prevent her (33) ________ doing what she had set out to do. A few days before the interview she had a very strange dream in which she gave birth to a beautiful baby. She was a little nervous and (34) ________about the dream and phoned to ask me what I thought it might mean. As I knew something about dreams, I was able to assure her that it only symbolized her (35) ________to do well in the interview. 

Question 33:

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 31 to 35:

The United States has many different types of families. While most American families are traditional, (31) __________ a father, a mother and one or more children, 22 percent of all American families in 1998 were headed by one parent, usually a woman. In a few families in the United States, there are no children. These (32) ___________ couples may believe that they would not make good parents; they may want freedom from responsibilities of childbearing; or, perhaps they (33) ___________ physically able to have children. Other families in the United States have one adult who is a stepparent. A stepmother or stepfather is a person who joins a family by marrying a father or a mother. Americans (34) ___________ and accept these different types of families. In the United States people have right to privacy and Americans do not believe in telling other Americans what type of family group they must belong to. They respect each other’s choices regarding family groups. Families are very important (35) ___________ Americans.  

Question 32:

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 31 to 35:

The United States has many different types of families. While most American families are traditional, (31) __________ a father, a mother and one or more children, 22 percent of all American families in 1998 were headed by one parent, usually a woman. In a few families in the United States, there are no children. These (32) ___________ couples may believe that they would not make good parents; they may want freedom from responsibilities of childbearing; or, perhaps they (33) ___________ physically able to have children. Other families in the United States have one adult who is a stepparent. A stepmother or stepfather is a person who joins a family by marrying a father or a mother. Americans (34) ___________ and accept these different types of families. In the United States people have right to privacy and Americans do not believe in telling other Americans what type of family group they must belong to. They respect each other’s choices regarding family groups. Families are very important (35) ___________ Americans.  

Question 31:

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks:

Last year, thieves broke into a Scottish stately home and stole only one thing: a rhino horn trophy, which at 1.5 meters was the longest in the world. Meanwhile, in China, pharmaceutical factories have been building up (31)______of antiques made from rhino horn, for the sole purpose of smashing them to powder to make the (32)_______ingredient of many of their medicines. And in Zimbabwe, 34 poachers died in 1990 in the search for the black rhino. Recently, conservationists met to (33)_______a campaign to persuade countries where rhino horn is still part of the traditional medicine to switch to substitutes. The biggest threat to the survival of the rhinoceros is the refusal of certain countries to enforce a ban on domestic trading in rhino horn. The rhino horn is included in many doses for disorders raging from fevers to nosebleeds. Horn, like fingernails, is made of keratin and has no proven medicinal (34)_______. Traditional substitutes, such as horn from buffalo or antelope, are regarded as second best. The battle is thought to be winnable. But it may be harder than the battle against the trade in ivory, for there is a (35)_______between the two commodities. Ivory is a luxury; rhino horn, people believe, could save the life of their child.  

Question 34:

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks:

Last year, thieves broke into a Scottish stately home and stole only one thing: a rhino horn trophy, which at 1.5 meters was the longest in the world. Meanwhile, in China, pharmaceutical factories have been building up (31)______of antiques made from rhino horn, for the sole purpose of smashing them to powder to make the (32)_______ingredient of many of their medicines. And in Zimbabwe, 34 poachers died in 1990 in the search for the black rhino. Recently, conservationists met to (33)_______a campaign to persuade countries where rhino horn is still part of the traditional medicine to switch to substitutes. The biggest threat to the survival of the rhinoceros is the refusal of certain countries to enforce a ban on domestic trading in rhino horn. The rhino horn is included in many doses for disorders raging from fevers to nosebleeds. Horn, like fingernails, is made of keratin and has no proven medicinal (34)_______. Traditional substitutes, such as horn from buffalo or antelope, are regarded as second best. The battle is thought to be winnable. But it may be harder than the battle against the trade in ivory, for there is a (35)_______between the two commodities. Ivory is a luxury; rhino horn, people believe, could save the life of their child.  

Question 35:

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks:

Last year, thieves broke into a Scottish stately home and stole only one thing: a rhino horn trophy, which at 1.5 meters was the longest in the world. Meanwhile, in China, pharmaceutical factories have been building up (31)______of antiques made from rhino horn, for the sole purpose of smashing them to powder to make the (32)_______ingredient of many of their medicines. And in Zimbabwe, 34 poachers died in 1990 in the search for the black rhino. Recently, conservationists met to (33)_______a campaign to persuade countries where rhino horn is still part of the traditional medicine to switch to substitutes. The biggest threat to the survival of the rhinoceros is the refusal of certain countries to enforce a ban on domestic trading in rhino horn. The rhino horn is included in many doses for disorders raging from fevers to nosebleeds. Horn, like fingernails, is made of keratin and has no proven medicinal (34)_______. Traditional substitutes, such as horn from buffalo or antelope, are regarded as second best. The battle is thought to be winnable. But it may be harder than the battle against the trade in ivory, for there is a (35)_______between the two commodities. Ivory is a luxury; rhino horn, people believe, could save the life of their child.  

Question 31:

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks:

Last year, thieves broke into a Scottish stately home and stole only one thing: a rhino horn trophy, which at 1.5 meters was the longest in the world. Meanwhile, in China, pharmaceutical factories have been building up (31)______of antiques made from rhino horn, for the sole purpose of smashing them to powder to make the (32)_______ingredient of many of their medicines. And in Zimbabwe, 34 poachers died in 1990 in the search for the black rhino. Recently, conservationists met to (33)_______a campaign to persuade countries where rhino horn is still part of the traditional medicine to switch to substitutes. The biggest threat to the survival of the rhinoceros is the refusal of certain countries to enforce a ban on domestic trading in rhino horn. The rhino horn is included in many doses for disorders raging from fevers to nosebleeds. Horn, like fingernails, is made of keratin and has no proven medicinal (34)_______. Traditional substitutes, such as horn from buffalo or antelope, are regarded as second best. The battle is thought to be winnable. But it may be harder than the battle against the trade in ivory, for there is a (35)_______between the two commodities. Ivory is a luxury; rhino horn, people believe, could save the life of their child.  

Question 32:

Question 32: 

Private school is not controlled by the government and is not supported by taxes or other public funds. A private school differs (31)__________ a public school, which operates with major support from government funds. Private schools are operated by religion groups or by independent organizations. Most private schools operate on a non-profit basis, although a few are run as businesses to make money for their owners. Private schools are (32)__________ chiefly by tuition, grants from their sponsors or contributions. Some private schools also have an invested money whose income is used to fund the school. In most countries, almost all schools were private until the early 1800’s. At that time, many government leaders began to encourage development of public schools to promote national progress by making education widely available to citizens. Today, the (33)__________ of public and private schools differs greatly from one country to another. In many developed countries, private schools offer a general focus on (34)__________ for college, a special focus on science, music or other subject areas; and religious instruction. The Roman Catholic Church is one of the largest sponsors of private schools (35)__________ the world.