Cho tứ diện đều $ABCD$ có cạnh bằng $5$ . Tính thể tích $V$ của khối nón nội tiếp tứ diện $ABCD$ .

Hình nón có đường sinh $l=2a$ và hợp với đáy góc $\alpha =60°$ . Diện tích toàn phần của hình nón bằng

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase thet best fits each of the numbered blanks from 24 to 28:

 Although it may come as a surprise to many people, postal services have existed in some parts of the world for thousands of years. There is ample evidence that a postal services existed among the Assyrians and Babylonians. In China a regular postal service was established in the seventh century BC, and over the centuries attained such a high level of efficiency that some 2000 years after its (24) _______ it won the admiration of travelers like Marco Polo. Efficient and highly developed postal services were also established in the Persia and Roman Empires. In ancient times, these services were mainly confined to the use of representative of the state; private citizens made use of slaves, merchants and the (25) _______ to send their messages and documents. In Medieval Europe, postal services were organized by emperors and by the papacy, (26) _______ private citizens continued to entrust their correspondence to various travelers. Later around the 13th century, universities and towns came to have the own messengers. However, it was not until the 14th century when merchants, the private citizens who had the greatest need for a speedy and regular exchange of correspondence, began to set (27) _______ regular courier services. The needs of business (28) _______ to the development of the postal services as we know it today.

Question 28:

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase thet best fits each of the numbered blanks from 24 to 28:

 Although it may come as a surprise to many people, postal services have existed in some parts of the world for thousands of years. There is ample evidence that a postal services existed among the Assyrians and Babylonians. In China a regular postal service was established in the seventh century BC, and over the centuries attained such a high level of efficiency that some 2000 years after its (24) _______ it won the admiration of travelers like Marco Polo. Efficient and highly developed postal services were also established in the Persia and Roman Empires. In ancient times, these services were mainly confined to the use of representative of the state; private citizens made use of slaves, merchants and the (25) _______ to send their messages and documents. In Medieval Europe, postal services were organized by emperors and by the papacy, (26) _______ private citizens continued to entrust their correspondence to various travelers. Later around the 13th century, universities and towns came to have the own messengers. However, it was not until the 14th century when merchants, the private citizens who had the greatest need for a speedy and regular exchange of correspondence, began to set (27) _______ regular courier services. The needs of business (28) _______ to the development of the postal services as we know it today.

Question 27: 

Choose the word or phrase (A, B, C or D) that best fits the blank space in the following passage:

                                                                A GOOD START TO A HOLIDAY

I had never been to Denmark before, and when I set out to catch the ferry in early May, I little (31) _______ that by the end of the trip I'd have made such lasting friendships.

I wanted to use my time well, so I had planned a route which would (32) _______ several small islands and various parts of the countryside. I arrived at Esbjerg, a convenient port for a cyclist’s arrival, where tourist information can be obtained and money changed. A cycle track (33) _______ out of town and down to Ribe, where I spent my first night.

In my experience, a person travelling alone sometimes meets with unexpected hospitality, and this trip was no exception. In Ribe, I got into conversation with a cheerful man who turned (34) _______ to be the local baker. He insisted that I should join his family for lunch, and, while we were eating, he contacted his daughter in Odense. Within minutes, he had (35) _______ for me to visit her and her family. Then I was sent on my way with a fresh loaf of bread to keep me going, and the feeling that this would turn out to be a wonderful holiday.

Question 32:

Choose the word or phrase (A, B, C or D) that best fits the blank space in the following passage:

                                                                A GOOD START TO A HOLIDAY

I had never been to Denmark before, and when I set out to catch the ferry in early May, I little (31) _______ that by the end of the trip I'd have made such lasting friendships.

I wanted to use my time well, so I had planned a route which would (32) _______ several small islands and various parts of the countryside. I arrived at Esbjerg, a convenient port for a cyclist’s arrival, where tourist information can be obtained and money changed. A cycle track (33) _______ out of town and down to Ribe, where I spent my first night.

In my experience, a person travelling alone sometimes meets with unexpected hospitality, and this trip was no exception. In Ribe, I got into conversation with a cheerful man who turned (34) _______ to be the local baker. He insisted that I should join his family for lunch, and, while we were eating, he contacted his daughter in Odense. Within minutes, he had (35) _______ for me to visit her and her family. Then I was sent on my way with a fresh loaf of bread to keep me going, and the feeling that this would turn out to be a wonderful holiday.

Question 31: 

Choose the word or phrase (A, B, C or D) that best fits the blank space in the following passage:

                                                                A GOOD START TO A HOLIDAY

I had never been to Denmark before, and when I set out to catch the ferry in early May, I little (31) _______ that by the end of the trip I'd have made such lasting friendships.

I wanted to use my time well, so I had planned a route which would (32) _______ several small islands and various parts of the countryside. I arrived at Esbjerg, a convenient port for a cyclist’s arrival, where tourist information can be obtained and money changed. A cycle track (33) _______ out of town and down to Ribe, where I spent my first night.

In my experience, a person travelling alone sometimes meets with unexpected hospitality, and this trip was no exception. In Ribe, I got into conversation with a cheerful man who turned (34) _______ to be the local baker. He insisted that I should join his family for lunch, and, while we were eating, he contacted his daughter in Odense. Within minutes, he had (35) _______ for me to visit her and her family. Then I was sent on my way with a fresh loaf of bread to keep me going, and the feeling that this would turn out to be a wonderful holiday.

Question 34:

Choose the word or phrase (A, B, C or D) that best fits the blank space in the following passage:

                                                                A GOOD START TO A HOLIDAY

I had never been to Denmark before, and when I set out to catch the ferry in early May, I little (31) _______ that by the end of the trip I'd have made such lasting friendships.

I wanted to use my time well, so I had planned a route which would (32) _______ several small islands and various parts of the countryside. I arrived at Esbjerg, a convenient port for a cyclist’s arrival, where tourist information can be obtained and money changed. A cycle track (33) _______ out of town and down to Ribe, where I spent my first night.

In my experience, a person travelling alone sometimes meets with unexpected hospitality, and this trip was no exception. In Ribe, I got into conversation with a cheerful man who turned (34) _______ to be the local baker. He insisted that I should join his family for lunch, and, while we were eating, he contacted his daughter in Odense. Within minutes, he had (35) _______ for me to visit her and her family. Then I was sent on my way with a fresh loaf of bread to keep me going, and the feeling that this would turn out to be a wonderful holiday.

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:

 In Germany, it's important to be serious in a work situation. They don't mix work and play so you shouldn't make jokes (31) _______ you do in the UK and USA when you first meet people. They work in a very organized way and prefer to do one thing at a time. They don't like interruptions or (32)_______ changes of schedule. Punctuality is very important so you should arrive on time for appointments. At meeting, it's important to follow the agenda and not interrupt (33) _______ speaker. If you give a presentation, you should focus (34) _______ facts and technical information and the quality of your company's products. You should also prepare well, as they may ask a lot of questions. Colleagues normally use the family names, and title - for example "Doctor" or "Professor", so you shouldn't use first names (35) _______ a person asks you to.

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:

 In Germany, it's important to be serious in a work situation. They don't mix work and play so you shouldn't make jokes (31) _______ you do in the UK and USA when you first meet people. They work in a very organized way and prefer to do one thing at a time. They don't like interruptions or (32)_______ changes of schedule. Punctuality is very important so you should arrive on time for appointments. At meeting, it's important to follow the agenda and not interrupt (33) _______ speaker. If you give a presentation, you should focus (34) _______ facts and technical information and the quality of your company's products. You should also prepare well, as they may ask a lot of questions. Colleagues normally use the family names, and title - for example "Doctor" or "Professor", so you shouldn't use first names (35) _______ a person asks you to.

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 from 31 to 35:

 In Germany, it's important to be serious in a work situation. They don't mix work and play so you shouldn't make jokes (31) _______ you do in the UK and USA when you first meet people. They work in a very organized way and prefer to do one thing at a time. They don't like interruptions or (32)_______ changes of schedule. Punctuality is very important so you should arrive on time for appointments. At meeting, it's important to follow the agenda and not interrupt (33) _______ speaker. If you give a presentation, you should focus (34) _______ facts and technical information and the quality of your company's products. You should also prepare well, as they may ask a lot of questions. Colleagues normally use the family names, and title - for example "Doctor" or "Professor", so you shouldn't use first names (35) _______ a person asks you to.

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:

 The warming of the Pacific Ocean has created weather pattern (31)_______ strongly affect the world. When the water is warm, the amount of rainfall in Indonesia and the surrounding regions decreases. Australia could (32)_______ experience a drought in many parts. On the other hand, Chile (which borders the Pacific Ocean) is preparing for severe rainstorms. In Pakistan and northwestern India, the weather pattern makes the rainy season weaker and makes the area much drier. This happening is called El Nino and is used (33)_______ weather forecasters to make long-range weather predictions. They also know that El Nino will bring unusually rain to the southwestern part of the United States and make the central part of the country drier at the same time. According to research, weather forecasters (34)_______ know about the coming weather with certainty. Now everything has become completely different. El Nino itself used to be predictable. It would occur every two to seven years. But now this weather pattern is becoming more frequent. We cannot say when and how often tornadoes or cyclones occur. Scientists are unsure of the reason for this (35)_______ on the global scale either.

Question 34: