Cho hình bình hành ABCD, biết $\overrightarrow{\mathrm{AB}} = \overrightarrow{\mathrm{a}}, \overrightarrow{\mathrm{CB}} = \overrightarrow{\mathrm{b}}$. Đẳng thức sai là

Cho tam giác ABC. Gọi A' là trung điểm cạnh BC và G là trọng tâm tamgiác ABC. Có 4 đẳng thức sau:
(a) $\overrightarrow{\mathrm{GA}} = -2\overrightarrow{\mathrm{GA}\text{'}}$
(b) $\overrightarrow{\mathrm{AA}\text{'}} = \frac{3}{2}\overrightarrow{\mathrm{GA}}$
(c) $\overrightarrow{\mathrm{GB}} + \overrightarrow{\mathrm{GC}} = 2\overrightarrow{\mathrm{GA}\text{'}}$
(d) $\frac{1}{2}\left(\overrightarrow{\mathrm{GB}} + \overrightarrow{\mathrm{GC}}\right) = -\frac{1}{3}\overrightarrow{\mathrm{A}\text{'}\mathrm{A}}$
Kết luận đúng trong các kết luận sau là

Các điểm và các vectơ sau cho trong hệ trục (O ; $\overrightarrow{\mathrm{i}}, \overrightarrow{\mathrm{j}}$) (giả thiết m, n, p, q là những số thực khác 0). Mệnh đề sai là

Cho hình chữ nhật ABCD, tâm O, I là trung điểm của BC. Tập hợp các điểm M sao cho $\left|\overrightarrow{\mathrm{MA}} + \overrightarrow{\mathrm{MC}}\right| =2\left|\overrightarrow{\mathrm{MB}} + \overrightarrow{\mathrm{MC}}\right|$ là:

Cho hai điểm M(1 ; 6) và N(6 ; 3). Tọa độ điểm P mà $\overrightarrow{\mathrm{PM}} = 2\overrightarrow{\mathrm{PN}}$ là

Trên trục (O ; $\overrightarrow{\mathrm{i}}$), biết độ dài đại số $\overline{\mathrm{PQ}}$ bằng 2. Cho các khẳng định sau:
(a) Vectơ $\overrightarrow{\mathrm{PQ}}$ cùng hướng với vectơ $\overrightarrow{\mathrm{OQ}}$
(b) Vectơ $\overrightarrow{\mathrm{PQ}}$ cùng hướng với vectơ $\overrightarrow{\mathrm{i}}$.
(c) Nếu toạ độ của điểm Q là 1 thì toạ độ của điểm P là 3.
(d) Nếu toạ độ của điểm Q là 1 thì toạ độ của điểm P là -1.
Số khẳng định đúng trong các khẳng định trên là

Cho tam giác ABC vuông cân tại A, O là trung điểm BC. Khẳng định sai là

Mệnh đề sai là

Cho hình bình hành ABCD, biết $\overrightarrow{\mathrm{AB}} = \overrightarrow{\mathrm{a}}, \overrightarrow{\mathrm{CB}} = \overrightarrow{\mathrm{b}}$. Đẳng thức đúng là

Cho hình bình hành ABCD, biết $\overrightarrow{\mathrm{AB}} = \overrightarrow{\mathrm{a}}, \overrightarrow{\mathrm{CB}} = \overrightarrow{\mathrm{b}}$. Đẳng thức sai là

Cho tam giác đều ABC. Đẳng thức sai là

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:

Whales are the largest animals in the world, and the gentlest creatures we know. Although the whale is very huge, it is not hindered at all by its size when it is in the water. Whales have tails that end like flippers. With just a gentle flick, it can propel itself forward. The skin of a whale is so smooth that it does not create any friction that can slow the whale down. A whale’s breathing hole is located on the top of its head, so it can breathe without having to completely push its head out of the water. Whales are protected from the cold seawater by body fat that is called blubber. Whales live in the ocean but, in terms of behaviours, they are more similar to humans than fish. They live in family groups and they even travel in groups when they have to migrate from cooler to warmer waters. The young stay with their parents for as long as fifteen years. Whales are known not to desert the ill or injured members; instead, they cradle them. When whales are in danger, there are people who go to great lengths to help them. One such case occurred in 1988, when three young whales were trapped in the sea. It was close to winter and the sea had begun to freeze over. Whales are mammals that require oxygen from the air, so the frozen ice was a great danger to them. All they had then was a tiny hole in the ice for them to breathe through. Volunteers from all over soon turned up to help these creatures. They cut holes in the ice to provide more breathing holes for the whales. These holes would also serve as guides for the whales so that they could swim to warmer waters.

Question 36: Which of the following best describes the main idea of this 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:

It's called 42 - the name taken from the answer to the meaning of life, from the science fiction series The Hitchhiker's Guide to the Galaxy. 42 was founded by French technology billionaire Xavier Niel, whose backing means there are no tuition fees and accommodation is free. Mr Niel and his co-founders come from the world of technology and start-ups, and they are trying to do to education what Facebook did to communication and Airbnb to accommodation. Students at 42 are given a choice of projects that they might be set in a job as a software engineer - perhaps to design a website or a computer game. They complete a project using resources freely available on the Internet and by seeking help from their fellow students, who work alongside them in a large open-plan room full of computers. Another student will then be randomly assigned to mark their work. The founders claim this method of learning makes up for shortcomings in the traditional education system, which they say encourages students to be passive recipients of knowledge. "Peer-to-peer learning develops students with the confidence to search for solutions by themselves, often in quite creative and ingenious ways." Like in computer games, the students are asked to design and they go up a level by completing a project. They graduate when they reach level 21, which usually takes three to five years. And at the end, there is a certificate but no formal degree. Recent graduates are now working at companies including IBM, Amazon, and Tesla, as well as starting their own firms. "The feedback we have had from employers is that our graduates are more apt to go off and find out information for themselves, rather than asking their supervisors what to do next," says Brittany Bir, chief operating officer of 42 in California and a graduate of its sister school in Paris. Ms Bir says 42's graduates will be better able to work with others and discuss and defend their ideas - an important skill in the “real world” of work. "This is particularly important in computer programming, where individuals are notorious for lacking certain human skills." she says. But could 42's model of teacherless learning work in mainstream universities? Brittany Bir admits 42's methods do not suit all students. "It suits individuals who are very disciplined and self-motivated, and who are not scared by having the freedom to work at their own pace." she says.

Question 43: According to the passage, 42 is_________.           

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:

Whales are the largest animals in the world, and the gentlest creatures we know. Although the whale is very huge, it is not hindered at all by its size when it is in the water. Whales have tails that end like flippers. With just a gentle flick, it can propel itself forward. The skin of a whale is so smooth that it does not create any friction that can slow the whale down. A whale’s breathing hole is located on the top of its head, so it can breathe without having to completely push its head out of the water. Whales are protected from the cold seawater by body fat that is called blubber. Whales live in the ocean but, in terms of behaviours, they are more similar to humans than fish. They live in family groups and they even travel in groups when they have to migrate from cooler to warmer waters. The young stay with their parents for as long as fifteen years. Whales are known not to desert the ill or injured members; instead, they cradle them. When whales are in danger, there are people who go to great lengths to help them. One such case occurred in 1988, when three young whales were trapped in the sea. It was close to winter and the sea had begun to freeze over. Whales are mammals that require oxygen from the air, so the frozen ice was a great danger to them. All they had then was a tiny hole in the ice for them to breathe through. Volunteers from all over soon turned up to help these creatures. They cut holes in the ice to provide more breathing holes for the whales. These holes would also serve as guides for the whales so that they could swim to warmer waters.

Question 42: According to the passage, why was the frozen ice on the sea surface a danger to whales?         

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:

Whales are the largest animals in the world, and the gentlest creatures we know. Although the whale is very huge, it is not hindered at all by its size when it is in the water. Whales have tails that end like flippers. With just a gentle flick, it can propel itself forward. The skin of a whale is so smooth that it does not create any friction that can slow the whale down. A whale’s breathing hole is located on the top of its head, so it can breathe without having to completely push its head out of the water. Whales are protected from the cold seawater by body fat that is called blubber. Whales live in the ocean but, in terms of behaviours, they are more similar to humans than fish. They live in family groups and they even travel in groups when they have to migrate from cooler to warmer waters. The young stay with their parents for as long as fifteen years. Whales are known not to desert the ill or injured members; instead, they cradle them. When whales are in danger, there are people who go to great lengths to help them. One such case occurred in 1988, when three young whales were trapped in the sea. It was close to winter and the sea had begun to freeze over. Whales are mammals that require oxygen from the air, so the frozen ice was a great danger to them. All they had then was a tiny hole in the ice for them to breathe through. Volunteers from all over soon turned up to help these creatures. They cut holes in the ice to provide more breathing holes for the whales. These holes would also serve as guides for the whales so that they could swim to warmer waters.

Question 41: The word “they” in paragraph 3 refers to______.         

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:

Whales are the largest animals in the world, and the gentlest creatures we know. Although the whale is very huge, it is not hindered at all by its size when it is in the water. Whales have tails that end like flippers. With just a gentle flick, it can propel itself forward. The skin of a whale is so smooth that it does not create any friction that can slow the whale down. A whale’s breathing hole is located on the top of its head, so it can breathe without having to completely push its head out of the water. Whales are protected from the cold seawater by body fat that is called blubber. Whales live in the ocean but, in terms of behaviours, they are more similar to humans than fish. They live in family groups and they even travel in groups when they have to migrate from cooler to warmer waters. The young stay with their parents for as long as fifteen years. Whales are known not to desert the ill or injured members; instead, they cradle them. When whales are in danger, there are people who go to great lengths to help them. One such case occurred in 1988, when three young whales were trapped in the sea. It was close to winter and the sea had begun to freeze over. Whales are mammals that require oxygen from the air, so the frozen ice was a great danger to them. All they had then was a tiny hole in the ice for them to breathe through. Volunteers from all over soon turned up to help these creatures. They cut holes in the ice to provide more breathing holes for the whales. These holes would also serve as guides for the whales so that they could swim to warmer waters.

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:

Whales are the largest animals in the world, and the gentlest creatures we know. Although the whale is very huge, it is not hindered at all by its size when it is in the water. Whales have tails that end like flippers. With just a gentle flick, it can propel itself forward. The skin of a whale is so smooth that it does not create any friction that can slow the whale down. A whale’s breathing hole is located on the top of its head, so it can breathe without having to completely push its head out of the water. Whales are protected from the cold seawater by body fat that is called blubber. Whales live in the ocean but, in terms of behaviours, they are more similar to humans than fish. They live in family groups and they even travel in groups when they have to migrate from cooler to warmer waters. The young stay with their parents for as long as fifteen years. Whales are known not to desert the ill or injured members; instead, they cradle them. When whales are in danger, there are people who go to great lengths to help them. One such case occurred in 1988, when three young whales were trapped in the sea. It was close to winter and the sea had begun to freeze over. Whales are mammals that require oxygen from the air, so the frozen ice was a great danger to them. All they had then was a tiny hole in the ice for them to breathe through. Volunteers from all over soon turned up to help these creatures. They cut holes in the ice to provide more breathing holes for the whales. These holes would also serve as guides for the whales so that they could swim to warmer waters.

Question 40: The word “tiny” in paragraph 3 probably means___ .         

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's called 42 - the name taken from the answer to the meaning of life, from the science fiction series The Hitchhiker's Guide to the Galaxy. 42 was founded by French technology billionaire Xavier Niel, whose backing means there are no tuition fees and accommodation is free. Mr Niel and his co-founders come from the world of technology and start-ups, and they are trying to do to education what Facebook did to communication and Airbnb to accommodation. Students at 42 are given a choice of projects that they might be set in a job as a software engineer - perhaps to design a website or a computer game. They complete a project using resources freely available on the Internet and by seeking help from their fellow students, who work alongside them in a large open-plan room full of computers. Another student will then be randomly assigned to mark their work. The founders claim this method of learning makes up for shortcomings in the traditional education system, which they say encourages students to be passive recipients of knowledge. "Peer-to-peer learning develops students with the confidence to search for solutions by themselves, often in quite creative and ingenious ways." Like in computer games, the students are asked to design and they go up a level by completing a project. They graduate when they reach level 21, which usually takes three to five years. And at the end, there is a certificate but no formal degree. Recent graduates are now working at companies including IBM, Amazon, and Tesla, as well as starting their own firms. "The feedback we have had from employers is that our graduates are more apt to go off and find out information for themselves, rather than asking their supervisors what to do next," says Brittany Bir, chief operating officer of 42 in California and a graduate of its sister school in Paris. Ms Bir says 42's graduates will be better able to work with others and discuss and defend their ideas - an important skill in the “real world” of work. "This is particularly important in computer programming, where individuals are notorious for lacking certain human skills." she says. But could 42's model of teacherless learning work in mainstream universities? Brittany Bir admits 42's methods do not suit all students. "It suits individuals who are very disciplined and self-motivated, and who are not scared by having the freedom to work at their own pace." she says.

Question 45: The author mentions “to design a website or a computer game” in paragraph 2 to illustrate _______.         

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's called 42 - the name taken from the answer to the meaning of life, from the science fiction series The Hitchhiker's Guide to the Galaxy. 42 was founded by French technology billionaire Xavier Niel, whose backing means there are no tuition fees and accommodation is free. Mr Niel and his co-founders come from the world of technology and start-ups, and they are trying to do to education what Facebook did to communication and Airbnb to accommodation. Students at 42 are given a choice of projects that they might be set in a job as a software engineer - perhaps to design a website or a computer game. They complete a project using resources freely available on the Internet and by seeking help from their fellow students, who work alongside them in a large open-plan room full of computers. Another student will then be randomly assigned to mark their work. The founders claim this method of learning makes up for shortcomings in the traditional education system, which they say encourages students to be passive recipients of knowledge. "Peer-to-peer learning develops students with the confidence to search for solutions by themselves, often in quite creative and ingenious ways." Like in computer games, the students are asked to design and they go up a level by completing a project. They graduate when they reach level 21, which usually takes three to five years. And at the end, there is a certificate but no formal degree. Recent graduates are now working at companies including IBM, Amazon, and Tesla, as well as starting their own firms. "The feedback we have had from employers is that our graduates are more apt to go off and find out information for themselves, rather than asking their supervisors what to do next," says Brittany Bir, chief operating officer of 42 in California and a graduate of its sister school in Paris. Ms Bir says 42's graduates will be better able to work with others and discuss and defend their ideas - an important skill in the “real world” of work. "This is particularly important in computer programming, where individuals are notorious for lacking certain human skills." she says. But could 42's model of teacherless learning work in mainstream universities? Brittany Bir admits 42's methods do not suit all students. "It suits individuals who are very disciplined and self-motivated, and who are not scared by having the freedom to work at their own pace." she says.

Question 44: The word “them” in paragraph 2 refers to________.         

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:

The elements other than hydrogen and helium exist in such small quantities that it is accurate to say that the universe is somewhat more than 25 percent helium by weight and somewhat less than 75 percent hydrogen. Astronomers have measured the abundance of helium throughout our galaxy and in other galaxies as well. Helium has been found in old stars, in relatively young ones, in interstellar gas, and in the distant objects known as quasars. Helium nuclei have also been found to be constituents of cosmic rays that fall on the earth (cosmic rays are not really a form of radiation; they consist of rapidly moving particles of numerous different kinds). It doesn’t seem to make very much difference where the helium is found. Its relative abundance never seems to vary much. In some places, there may be slightly more of it; in others, slightly less, but the ratio of helium to hydrogen nuclei always remains about the same. Helium is created in stars. In fact, nuclear reactions that convert hydrogen to helium are responsible for most of the energy that stars produce. However, the amount of helium that could have been produced in this manner can be calculated, and it turns out to be no more than a few percent. The universe has not existed long enough for this figure to be significant greater. Consequently, if the universe is somewhat more than 25 percent helium now, then it must have been about 25 percent helium at a time near the beginning. However, when the universe was less than one minute old, no helium could have existed. Calculations indicate that before this time temperature were too high and particles of matter were moving around much too rapidly. It was only after the one-minute point that helium could exist. By this time, the universe had cooled so sufficiently that neutrons and protons could stick together. But the nuclear reactions that led to the formations of helium went on for only relatively short time. By the time the universe was a few minutes old, helium production had effectively ceased.

 Question: Most of the helium in the universe was formed ______

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:

The elements other than hydrogen and helium exist in such small quantities that it is accurate to say that the universe is somewhat more than 25 percent helium by weight and somewhat less than 75 percent hydrogen. Astronomers have measured the abundance of helium throughout our galaxy and in other galaxies as well. Helium has been found in old stars, in relatively young ones, in interstellar gas, and in the distant objects known as quasars. Helium nuclei have also been found to be constituents of cosmic rays that fall on the earth (cosmic rays are not really a form of radiation; they consist of rapidly moving particles of numerous different kinds). It doesn’t seem to make very much difference where the helium is found. Its relative abundance never seems to vary much. In some places, there may be slightly more of it; in others, slightly less, but the ratio of helium to hydrogen nuclei always remains about the same. Helium is created in stars. In fact, nuclear reactions that convert hydrogen to helium are responsible for most of the energy that stars produce. However, the amount of helium that could have been produced in this manner can be calculated, and it turns out to be no more than a few percent. The universe has not existed long enough for this figure to be significant greater. Consequently, if the universe is somewhat more than 25 percent helium now, then it must have been about 25 percent helium at a time near the beginning. However, when the universe was less than one minute old, no helium could have existed. Calculations indicate that before this time temperature were too high and particles of matter were moving around much too rapidly. It was only after the one-minute point that helium could exist. By this time, the universe had cooled so sufficiently that neutrons and protons could stick together. But the nuclear reactions that led to the formations of helium went on for only relatively short time. By the time the universe was a few minutes old, helium production had effectively ceased.

Question: The creation of helium within stars ______         

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:

The elements other than hydrogen and helium exist in such small quantities that it is accurate to say that the universe is somewhat more than 25 percent helium by weight and somewhat less than 75 percent hydrogen. Astronomers have measured the abundance of helium throughout our galaxy and in other galaxies as well. Helium has been found in old stars, in relatively young ones, in interstellar gas, and in the distant objects known as quasars. Helium nuclei have also been found to be constituents of cosmic rays that fall on the earth (cosmic rays are not really a form of radiation; they consist of rapidly moving particles of numerous different kinds). It doesn’t seem to make very much difference where the helium is found. Its relative abundance never seems to vary much. In some places, there may be slightly more of it; in others, slightly less, but the ratio of helium to hydrogen nuclei always remains about the same. Helium is created in stars. In fact, nuclear reactions that convert hydrogen to helium are responsible for most of the energy that stars produce. However, the amount of helium that could have been produced in this manner can be calculated, and it turns out to be no more than a few percent. The universe has not existed long enough for this figure to be significant greater. Consequently, if the universe is somewhat more than 25 percent helium now, then it must have been about 25 percent helium at a time near the beginning. However, when the universe was less than one minute old, no helium could have existed. Calculations indicate that before this time temperature were too high and particles of matter were moving around much too rapidly. It was only after the one-minute point that helium could exist. By this time, the universe had cooled so sufficiently that neutrons and protons could stick together. But the nuclear reactions that led to the formations of helium went on for only relatively short time. By the time the universe was a few minutes old, helium production had effectively ceased.

Question: The word "vary" is closest in meaning to ______