Cho mệnh đề "  là một số vô tỉ". Mệnh đề phủ đinh của mệnh đề trên trong các mệnh đề sau đây là

Cho A là tập hợp các số tự nhiên chẵn, B là tập hợp các số tự nhiên chia hết cho 3, C là tập hợp các số tự nhiên chia hết cho 6. Kết quả đúng trong các kết quả sau đây là

Tập hợp sau đây là tập hợp rỗng là

Câu sau đây là một mệnh đề là

Kí hiệu |X| là số phần tử của tập hợp X. Cho hai tập hợp A và B khác tập hợp rỗng. Xét các mệnh đề sau, mệnh đề đúng là
I. A ∩ B = Ø ⇒ |A| + |B| = |A ∪ B|
II. A ∩ B ≠ Ø ⇒ |A| + |B| = |A ∪ B| - |A ∩ B|
III. A ∩ B ≠ Ø ⇒ |A| + |B| = |A ∪ B| + |A ∩ B|

Trong số gần đúng a = 9054632 của số đúng  có bao nhiêu chữ số chắc, biết rằng sai số tuyệt đối bằng 14.

Xét khẳng định P: "∀x ∈ R , x² + x +  > 0". Khẳng định đúng là

Cho A là tập hợp các ước nguyên dương của 24, B là tập hợp các ước nguyên dương của 18. Những kết quả sai trong các kết quả cho sau đây là

(a) Tập A có 8 phần tử.

(b) Tập B có 6 phần tử.

(c) Tập A ∪ B có 14 phần tử.

(d) Tập A ∩ B có 4 phần tử.

(e) Tập A \ B có 2 phần tử.

(h) Tập B \ A có 2 phần tử.

Tập hợp sau đây khác tập hợp rỗng là

Kí hiệu A là tập hợp các học sinh của một lớp học. T là tập hợp các học sinh giỏi toán; V là tập hợp các học sinh giỏi văn của lớp này. Giả sử x là học sinh giỏi toán mà không giỏi văn, y là học sinh giỏi văn mà không giỏi toán. Những mệnh đề đúng trong các mệnh đề sau là

(a) x ∈ A \ V
(b) x ∈ T \ V
(c) y ∈ T ∩ V
(d) y ∈ T ∪ V 
(e) y ∈ V \ T

Cho mệnh đề "  là một số vô tỉ". Mệnh đề phủ đinh của mệnh đề trên trong các mệnh đề sau đây là

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 24 to 28:

The expression on your face can usually dramatically alter your feelings and perceptions, and it has been proved that deliberately smiling or frowning can create corresponding emotional responses. The idea was first (24) _______ by a French physiologist, Israel Waynbaum, in 1906. He believed that different facial (25) _______ affected the flow of blood to the brain, and that this could create positive or negative feelings. A happy smile or irrepressible laughter increased the blood flow and contributed to joyful feelings. But sad angry expressions decreased the flow of oxygen-carrying blood, and created a vicious (26) _______ of gloom and depression by effectively starving the brain of essential fuel. Psychologist Robert Zajone rediscovered this early subject, and suggests that the temperature of the brain could affect the production and synthesis of neurotransmitters, which definitely influence our moods and energy levels. He argues that an impaired blood flow could not only deprive the brain of oxygen, but also create further chemical imbalance (27) _______ inhibiting these vital hormonal messages. Zajone goes on to propose that our brains remember smiling associated with being happy, and that by deliberately smiling through your tears you can (28) _______ your brain to release uplifting neurotransmitters replacing a depression condition with a happier one. People suffering from psychosomatic ailment, depression and anxiety states could benefit from simply exercising their zygomatic muscles, which pull the corners of the mouth up and back to form a smile several times an hour.

Question 25:        

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 24 to 28:

The expression on your face can usually dramatically alter your feelings and perceptions, and it has been proved that deliberately smiling or frowning can create corresponding emotional responses. The idea was first (24) _______ by a French physiologist, Israel Waynbaum, in 1906. He believed that different facial (25) _______ affected the flow of blood to the brain, and that this could create positive or negative feelings. A happy smile or irrepressible laughter increased the blood flow and contributed to joyful feelings. But sad angry expressions decreased the flow of oxygen-carrying blood, and created a vicious (26) _______ of gloom and depression by effectively starving the brain of essential fuel. Psychologist Robert Zajone rediscovered this early subject, and suggests that the temperature of the brain could affect the production and synthesis of neurotransmitters, which definitely influence our moods and energy levels. He argues that an impaired blood flow could not only deprive the brain of oxygen, but also create further chemical imbalance (27) _______ inhibiting these vital hormonal messages. Zajone goes on to propose that our brains remember smiling associated with being happy, and that by deliberately smiling through your tears you can (28) _______ your brain to release uplifting neurotransmitters replacing a depression condition with a happier one. People suffering from psychosomatic ailment, depression and anxiety states could benefit from simply exercising their zygomatic muscles, which pull the corners of the mouth up and back to form a smile several times an hour.

Question 24:      

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 1 to 5:

In the past, it was common for three or more (1) ______ to live together in the same roof. Nowadays most elderly people live (2) ________their own. They generally stay in contact with their children or grandchildren but might live in the different part of the country. People also live together, often 20 years after they have (3) _________from their job. Modern American culture tends to value youth rather than age. This create an interesting challenge for older people and for the country. American families also have troubles. They are the divorce rate, the fact that working mothers might have (4)____________ time with their children, and the problems that parents and children sometimes misunderstand each other. (5)_________, family is still at the center of most people’s lives. 

Question 2:

Cho m gam hỗn hợp bột X gồm ba kim loại Zn, Cr, Sn có số mol bằng nhau tác dụng hết với lượng dư dung dịch HCl loãng, nóng thu được dung dịch Y và khí H2. Cô cạn dung dịch Y thu được 8,98 gam muối khan. Nếu cho m gam hỗn hợp X tác dụng hoàn toàn với O2 (dư) để tạo hỗn hợp 3 oxit thì thể tích khí O2(đktc) phản ứng là         

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 1 to 5:

In the past, it was common for three or more (1) ______ to live together in the same roof. Nowadays most elderly people live (2) ________their own. They generally stay in contact with their children or grandchildren but might live in the different part of the country. People also live together, often 20 years after they have (3) _________from their job. Modern American culture tends to value youth rather than age. This create an interesting challenge for older people and for the country. American families also have troubles. They are the divorce rate, the fact that working mothers might have (4)____________ time with their children, and the problems that parents and children sometimes misunderstand each other. (5)_________, family is still at the center of most people’s lives. 

Question 1:

Hỗn hợp A gồm Fe, Cu, Al, Mg (có tỉ lệ mol tương ứng là 1:1:2:2). Hòa tan 22,2 g hỗn hợp A cần vừa đủ 950ml dung dịch HNO3 2M sau các phản ứng hoàn toàn thu được dung dịch X và V lít (đktc) hỗn hợp khí Y gồm NO, N2, N2O, NO2; biết . Cô cạn rất cẩn thận dung dịch X thu được 117,2g muối. Giá trị V là      

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 current global extinction rate is estimated at about 20,000 species per year, exponentially greater than the background extinction rate. Many (31) _____ believe that we are in the middle of the greatest mass extinction episode since the disappearance of the dinosaurs 65 million years ago. From what is known about present-day populations and from (32) _____ theory, the change in either the physical or the biological environment is the key to extinction. However, the vulnerability of a species depends (33) _____ a wide variety of factors, such as its total population size, geographical distribution, reproductive ability, ecological relations with other species, and genetic characteristics. For example, more emphasis is put on the greater vulnerability of species that reproduce slowly as contrasted with those that reproduce (34) _____. Other factors, such as food-plant specialization, may make many fast reproducers more vulnerable than species that reproduce more slowly. No matter (35) _____ fast an insect species that depends on a certain plan can reproduce; it will still go extinct if that plant's habitat is destroyed. It has been estimated that about one half billion species have lived at one time or another, and today's existing species are only 2% of those that have ever evolved. The other 98% have either died out or evolved into something sufficiently different to be called a new species.

Question 32: 

Cho 13,36g hỗn hợp X gồm Cu, Fe3O4 vào dung dịch H2SO4 đặc nóng dư được V1 lít SO2 và dung dịch Y. Cho Y phản ứng với NaOH dư được kết tủa T, nung kết tủa này đến khối lượng không đổi được 15,2g chất rắn Q. Nếu cũng cho lượng X như trên vào 400ml dung dịch P chứa HNO3 và H2SO4 thấy có V2 lít NO duy nhất thoát ra và còn 0,64g kim loại chưa tan hết. Các phản ứng xảy ra hoàn toàn và các khí đo ở đktc. Giá trị V1 và V2 là           

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 current global extinction rate is estimated at about 20,000 species per year, exponentially greater than the background extinction rate. Many (31) _____ believe that we are in the middle of the greatest mass extinction episode since the disappearance of the dinosaurs 65 million years ago. From what is known about present-day populations and from (32) _____ theory, the change in either the physical or the biological environment is the key to extinction. However, the vulnerability of a species depends (33) _____ a wide variety of factors, such as its total population size, geographical distribution, reproductive ability, ecological relations with other species, and genetic characteristics. For example, more emphasis is put on the greater vulnerability of species that reproduce slowly as contrasted with those that reproduce (34) _____. Other factors, such as food-plant specialization, may make many fast reproducers more vulnerable than species that reproduce more slowly. No matter (35) _____ fast an insect species that depends on a certain plan can reproduce; it will still go extinct if that plant's habitat is destroyed. It has been estimated that about one half billion species have lived at one time or another, and today's existing species are only 2% of those that have ever evolved. The other 98% have either died out or evolved into something sufficiently different to be called a new species.

Question 33:

Hỗn hợp X gồm CuSO4, FeSO4, Fe2(SO4)3 có chứa 21,92% S về khối lượng. Lấy 200g hỗn hợp X tác dụng với NaOH dư, lọc lấy kết tủa đem nung trong không khí đến khối lượng không đổi thu được 93,6 gam chất rắn. Thành phần phần trăm về khối lượng FeSO4 trong hỗn hợp X là