Cho các chất sau: etyl amin, đimetyl amin, anilin và amoniac. Thứ tự ứng với tính bazơ tăng dần 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 27 to 38:

On a winter afternoon, a dozen male Northern fur seals are on an island off south - western Alaska. To look at them, fighting for territory on the rocks, it’s hard to imagine that they are at the (27)____________of a baffling scientific mystery: why is this species beginning to disappear? These seals - which can weigh up to 270 kilograms - have an important and symbolic (28)_________in Alaska’s history. Their soft and luxurious fur, the coveted prize during the huge commercial sea harvests that were legal here in the Bering Sea through the early 20th century, was once so valuable it (29)_________Alaska’s economy. Starting in the 1950s, for reasons that are (30)_______because the harvests by then tended to be fairly small, the seal population began a slow decline. But lately it has been falling drastically, declining at an alarming (31)________of 6 per cent a year since 1998. From a (32)_________ of more than 2 million in Alaska in 1948, their numbers have fallen to about 1 million. So (33)________, no one has been able to establish a precise cause for this, although theories (34)___________. The seal's food supply may be (35)________, or another species may be (36)________on the seals - perhaps killer whales, which no longer have as many great whales to eat because of harvesting of those mammals. Some people have suggested that the decline can be (37)______to entanglement in fishing nets, but scientists say they doubt that this alone could (38)_________the recent population decline.

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 27 to 38:

On a winter afternoon, a dozen male Northern fur seals are on an island off south - western Alaska. To look at them, fighting for territory on the rocks, it’s hard to imagine that they are at the (27)____________of a baffling scientific mystery: why is this species beginning to disappear? These seals - which can weigh up to 270 kilograms - have an important and symbolic (28)_________in Alaska’s history. Their soft and luxurious fur, the coveted prize during the huge commercial sea harvests that were legal here in the Bering Sea through the early 20th century, was once so valuable it (29)_________Alaska’s economy. Starting in the 1950s, for reasons that are (30)_______because the harvests by then tended to be fairly small, the seal population began a slow decline. But lately it has been falling drastically, declining at an alarming (31)________of 6 per cent a year since 1998. From a (32)_________ of more than 2 million in Alaska in 1948, their numbers have fallen to about 1 million. So (33)________, no one has been able to establish a precise cause for this, although theories (34)___________. The seal's food supply may be (35)________, or another species may be (36)________on the seals - perhaps killer whales, which no longer have as many great whales to eat because of harvesting of those mammals. Some people have suggested that the decline can be (37)______to entanglement in fishing nets, but scientists say they doubt that this alone could (38)_________the recent population decline.

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 27 to 38:

On a winter afternoon, a dozen male Northern fur seals are on an island off south - western Alaska. To look at them, fighting for territory on the rocks, it’s hard to imagine that they are at the (27)____________of a baffling scientific mystery: why is this species beginning to disappear? These seals - which can weigh up to 270 kilograms - have an important and symbolic (28)_________in Alaska’s history. Their soft and luxurious fur, the coveted prize during the huge commercial sea harvests that were legal here in the Bering Sea through the early 20th century, was once so valuable it (29)_________Alaska’s economy. Starting in the 1950s, for reasons that are (30)_______because the harvests by then tended to be fairly small, the seal population began a slow decline. But lately it has been falling drastically, declining at an alarming (31)________of 6 per cent a year since 1998. From a (32)_________ of more than 2 million in Alaska in 1948, their numbers have fallen to about 1 million. So (33)________, no one has been able to establish a precise cause for this, although theories (34)___________. The seal's food supply may be (35)________, or another species may be (36)________on the seals - perhaps killer whales, which no longer have as many great whales to eat because of harvesting of those mammals. Some people have suggested that the decline can be (37)______to entanglement in fishing nets, but scientists say they doubt that this alone could (38)_________the recent population decline.

Question 27: 

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 27 to 38:

On a winter afternoon, a dozen male Northern fur seals are on an island off south - western Alaska. To look at them, fighting for territory on the rocks, it’s hard to imagine that they are at the (27)____________of a baffling scientific mystery: why is this species beginning to disappear? These seals - which can weigh up to 270 kilograms - have an important and symbolic (28)_________in Alaska’s history. Their soft and luxurious fur, the coveted prize during the huge commercial sea harvests that were legal here in the Bering Sea through the early 20th century, was once so valuable it (29)_________Alaska’s economy. Starting in the 1950s, for reasons that are (30)_______because the harvests by then tended to be fairly small, the seal population began a slow decline. But lately it has been falling drastically, declining at an alarming (31)________of 6 per cent a year since 1998. From a (32)_________ of more than 2 million in Alaska in 1948, their numbers have fallen to about 1 million. So (33)________, no one has been able to establish a precise cause for this, although theories (34)___________. The seal's food supply may be (35)________, or another species may be (36)________on the seals - perhaps killer whales, which no longer have as many great whales to eat because of harvesting of those mammals. Some people have suggested that the decline can be (37)______to entanglement in fishing nets, but scientists say they doubt that this alone could (38)_________the recent population decline.

Question 29:

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 27 to 38:

On a winter afternoon, a dozen male Northern fur seals are on an island off south - western Alaska. To look at them, fighting for territory on the rocks, it’s hard to imagine that they are at the (27)____________of a baffling scientific mystery: why is this species beginning to disappear? These seals - which can weigh up to 270 kilograms - have an important and symbolic (28)_________in Alaska’s history. Their soft and luxurious fur, the coveted prize during the huge commercial sea harvests that were legal here in the Bering Sea through the early 20th century, was once so valuable it (29)_________Alaska’s economy. Starting in the 1950s, for reasons that are (30)_______because the harvests by then tended to be fairly small, the seal population began a slow decline. But lately it has been falling drastically, declining at an alarming (31)________of 6 per cent a year since 1998. From a (32)_________ of more than 2 million in Alaska in 1948, their numbers have fallen to about 1 million. So (33)________, no one has been able to establish a precise cause for this, although theories (34)___________. The seal's food supply may be (35)________, or another species may be (36)________on the seals - perhaps killer whales, which no longer have as many great whales to eat because of harvesting of those mammals. Some people have suggested that the decline can be (37)______to entanglement in fishing nets, but scientists say they doubt that this alone could (38)_________the recent population decline.

Question 28: 

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

 Personal space is a term that refers (24)_____the distance we like to keep between ourselves and other people. When (25) ______we do not know well gets too close we usually begin to feel uncomfortable. If a business colleague comes closer than 1.2 meters, the most common response is to move (26)______. Some interesting (27)______have been done in libraries. If strangers come too close, many people get up and leave the building; others use different methods such as turning their back on the intruder. Living in cities has made people develop new skills for dealing with situations where they are very close to strangers. Most people on crowded trains try not to look at strangers; they avoid skin contact, and apologize if hands touch by mistake. People use newspapers (28) ______a barrier between themselves and other people, and if they do not have one, they stare into the distance, making sure they are not looking into anyone’s eyes.

Question 24:

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

                                                               LOOK ON THE BRIGHT SIDE       

Do you ever wish you were more optimistic, some one who always (21)_____ to be successful? Having some one around who always fears the worst isn’t really a lot of (22)_____we all know someone who sees a single cloud on a sunny day and says: “It looks like rain.”. But if you catch yourself thinking such things, it’s important to do something (23)_____ it. You can change your view of life, (24)_____ to psychologists, it only takes a little effort, and you’ll find life more rewarding as a (25)______. Optimism, they say, is partly about self-respect and confidence, but it’s also a more positive way of looking at life and all it has to offer. Optimists are more (26)_______to start new projects and generally more prepared to take risks. Upbringing is obviously very important in forming your (27)_______ to the world. Some people are brought up to (28)______too much on others and grow up forever blaming other people when anything goes wrong. Most optimists, on the (29) _____hand, have been brought up not to regard failure as the end of the world - they just (30)_____with their lives.

Question 26:

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

                                                               LOOK ON THE BRIGHT SIDE       

Do you ever wish you were more optimistic, some one who always (21)_____ to be successful? Having some one around who always fears the worst isn’t really a lot of (22)_____we all know someone who sees a single cloud on a sunny day and says: “It looks like rain.”. But if you catch yourself thinking such things, it’s important to do something (23)_____ it. You can change your view of life, (24)_____ to psychologists, it only takes a little effort, and you’ll find life more rewarding as a (25)______. Optimism, they say, is partly about self-respect and confidence, but it’s also a more positive way of looking at life and all it has to offer . Optimists are more (26)_______to start new projects and generally more prepared to take risks. Upbringing is obviously very important in forming your (27)_______ to the world. Some people are brought up to (28)______too much on others and grow up forever blaming other people when anything goes wrong. Most optimists, on the (29) _____hand, have been brought up not to regard failure as the end of the world - they just (30)_____with their lives.

Question 27:

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

                                                               LOOK ON THE BRIGHT SIDE       

Do you ever wish you were more optimistic, some one who always (21)_____ to be successful? Having some one around who always fears the worst isn’t really a lot of (22)_____we all know someone who sees a single cloud on a sunny day and says: “It looks like rain.”. But if you catch yourself thinking such things, it’s important to do something (23)_____ it. You can change your view of life, (24)_____ to psychologists, it only takes a little effort, and you’ll find life more rewarding as a (25)______. Optimism, they say, is partly about self-respect and confidence, but it’s also a more positive way of looking at life and all it has to offer. Optimists are more (26)_______to start new projects and generally more prepared to take risks. Upbringing is obviously very important in forming your (27)_______ to the world. Some people are brought up to (28)______too much on others and grow up forever blaming other people when anything goes wrong. Most optimists, on the (29) _____hand, have been brought up not to regard failure as the end of the world - they just (30)_____with their lives.

Question 24:

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

                                                               LOOK ON THE BRIGHT SIDE       

Do you ever wish you were more optimistic, some one who always (21)_____ to be successful? Having some one around who always fears the worst isn’t really a lot of (22)_____we all know someone who sees a single cloud on a sunny day and says: “It looks like rain.”. But if you catch yourself thinking such things, it’s important to do something (23)_____ it. You can change your view of life, (24)_____ to psychologists, it only takes a little effort, and you’ll find life more rewarding as a (25)______. Optimism, they say, is partly about self-respect and confidence, but it’s also a more positive way of looking at life and all it has to offer. Optimists are more (26)_______to start new projects and generally more prepared to take risks. Upbringing is obviously very important in forming your (27)_______ to the world. Some people are brought up to (28)______too much on others and grow up forever blaming other people when anything goes wrong. Most optimists, on the (29) _____hand, have been brought up not to regard failure as the end of the world - they just (30)_____with their lives.

Question 25: