Mark the letter A, B, C, or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions.

Mark the letter A, B, C, or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions.

Mark the letter A, B, C, or D on your answer sheet to indicate the word that differs from the other three in the position of primary stress in each of the following questions.

Mark the letter A, B, C, or D on your answer sheet to indicate the word that differs from the other three in the position of primary stress in each of the following questions.

Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions.
Neither (A) the director nor any (B) members of the staff is (C) working overtime (D) today.

Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions.
People live (A) in big cities (B) often have trouble (C) making friends (D).

Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions.

When attempt (A) to explain (B) children’s (C) good preferences, researchers are faced with (D) contradictions.

My supervisor is angry with me. I didn’t do all the work that I _____ last week.

The Mona Lisa, painted in Florence in 1504 by Leonardo da Vinci, is a name which is perhaps more recognizable to people throughout the world _____ of da Vinci himself.

Which phosphorus, a substance _____ in matches, is so flammable that it burst into flame upon contact with the air.

If he _____ harder, he would have passed the exam.

My grandmother was a lovely person who_____ pleasure from helping others.

You have to _____ your revision tonight. Or it’s too late.

A child’s existence seems so_____ in the arms of its mother.

Despite her poor exam results, Alice put a _____ face on the situation.

My father has decided to _____ a beard to cover a small scar he has on his chin.

The fall of the dictatorship of Miguel Primode Riverra _____ the establishment of the Second Spanish Republic.

If you want a flat in the centre of the city, you have to pay through the _____ for it.

Among bees _____ a highly elaborate form of communication.

As they came under heavy fire, the captain ordered his men to _____.

The manager did not offer her the job because of her untidy_____.

– Anna: “Come on, Peter. I want to show you something?”

– Peter: “Oh how nice of you! I _____ you _____ to bring me a gift.”

– A: “Do you like pop music or jazz?”

– B: “_____. I prefer classical music.”

Mark the letter A, B, C, or D on your answer sheet to indicate the word(s) CLOSEST in meaning to the underlined word(s) in each of the following questions.
The red cross made an equitable distribution of the bread to the starving children.

Mark the letter A, B, C, or D on your answer sheet to indicate the word(s) CLOSEST in meaning to the underlined word(s) in each of the following questions.
On the second thought, I believe I will go with you to the theater.

Mark the letter A, B, C, or D on your answer sheet to indicate the word(s) OPPOSITE in meaning to the underlined word(s) in each of the following questions.
Sales have been slow, but the market for contemporary art is expected to pick up soon.

Mark the letter A, B, C, or D on your answer sheet to indicate the word(s) OPPOSITE in meaning to the underlined word(s) in each of the following questions.
They’ll talk to us about the new project in detail.

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that is closest in meaning to each of the following questions.
I am much worse than Josh is at physics.

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that is closest in meaning to each of the following questions.
We were already late for the show by the time we had found a taxi.

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that is closest in meaning to each of the following questions.
“You should take more care of your health or you may regret it,” the doctor said to her.

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions.
You need time to arrange a party. If not, it is better not to have one.

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions.
The pop star is recognized wherever she goes. Therefore, she always has a bodyguard.

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 33 to 37.

All plants rely on nutrients taken from the soil in order to survive. However, in areas where the soil does not contain enough (33) _____ nutrients, some plants have adapted to supplement their diets from another source: living organisms. Though they are few in number, carnivorous plants are (34)_____ fascinating beings that “eat” anything from one-celled organisms to insects in order to survive. They are commonly found in marshlands. Carnivorous plants feature one of several types of “traps” to ensnare prey, which they consume to make up for nutrients that may be missing from the soil. While there are over 400 species of carnivorous plants in the world today, some are more prevalent than others.

The most well-known of these plants are the snap traps, which include the Venus flytrap. Snap traps are easily identified by their leaves, which are separated into two lobes that have the ability to fold together. Inside the lobes, the surface is covered with tiny hairs that are (35) _____ to movement. When the plant’s prey brushes against the hairs, it triggers a closing mechanism that rapidly brings the two lobes together, trapping the prey securely inside. The response of the traps is phenomenal (36)_____ speed: the time between triggering the hairs and snapping shut is less than a second. As the prey struggles inside the trap, it only triggers more hairs, causing the leaves to tighten their grip. The plant then secrets liquid chemicals from special glands into the trap to dissolve the prey and absorb all of its nutrients. Besides the Venus flytrap, only one other type of snap trap exists today, (37)_____ to as the waterwheel plant. The two share a common ancestor and differ only in a few ways. For instance, the waterwheel is an aquatic plant, while the flytrap is exclusively terrestrial. In addition, the flytrap feeds primarily on arthropods like spiders, while the waterwheel lives off simple invertebrates, like certain types of plankton.

Điền vào số (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 33 to 37. 

All plants rely on nutrients taken from the soil in order to survive. However, in areas where the soil does not contain enough (33) _____ nutrients, some plants have adapted to supplement their diets from another source: living organisms. Though they are few in number, carnivorous plants are (34)_____ fascinating beings that “eat” anything from one-celled organisms to insects in order to survive. They are commonly found in marshlands. Carnivorous plants feature one of several types of “traps” to ensnare prey, which they consume to make up for nutrients that may be missing from the soil. While there are over 400 species of carnivorous plants in the world today, some are more prevalent than others.

The most well-known of these plants are the snap traps, which include the Venus flytrap. Snap traps are easily identified by their leaves, which are separated into two lobes that have the ability to fold together. Inside the lobes, the surface is covered with tiny hairs that are (35) _____ to movement. When the plant’s prey brushes against the hairs, it triggers a closing mechanism that rapidly brings the two lobes together, trapping the prey securely inside. The response of the traps is phenomenal (36)_____ speed: the time between triggering the hairs and snapping shut is less than a second. As the prey struggles inside the trap, it only triggers more hairs, causing the leaves to tighten their grip. The plant then secrets liquid chemicals from special glands into the trap to dissolve the prey and absorb all of its nutrients. Besides the Venus flytrap, only one other type of snap trap exists today, (37)_____ to as the waterwheel plant. The two share a common ancestor and differ only in a few ways. For instance, the waterwheel is an aquatic plant, while the flytrap is exclusively terrestrial. In addition, the flytrap feeds primarily on arthropods like spiders, while the waterwheel lives off simple invertebrates, like certain types of plankton.

Điền vào số (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 33 to 37. 

All plants rely on nutrients taken from the soil in order to survive. However, in areas where the soil does not contain enough (33) _____ nutrients, some plants have adapted to supplement their diets from another source: living organisms. Though they are few in number, carnivorous plants are (34)_____ fascinating beings that “eat” anything from one-celled organisms to insects in order to survive. They are commonly found in marshlands. Carnivorous plants feature one of several types of “traps” to ensnare prey, which they consume to make up for nutrients that may be missing from the soil. While there are over 400 species of carnivorous plants in the world today, some are more prevalent than others.

The most well-known of these plants are the snap traps, which include the Venus flytrap. Snap traps are easily identified by their leaves, which are separated into two lobes that have the ability to fold together. Inside the lobes, the surface is covered with tiny hairs that are (35) _____ to movement. When the plant’s prey brushes against the hairs, it triggers a closing mechanism that rapidly brings the two lobes together, trapping the prey securely inside. The response of the traps is phenomenal (36)_____ speed: the time between triggering the hairs and snapping shut is less than a second. As the prey struggles inside the trap, it only triggers more hairs, causing the leaves to tighten their grip. The plant then secrets liquid chemicals from special glands into the trap to dissolve the prey and absorb all of its nutrients. Besides the Venus flytrap, only one other type of snap trap exists today, (37)_____ to as the waterwheel plant. The two share a common ancestor and differ only in a few ways. For instance, the waterwheel is an aquatic plant, while the flytrap is exclusively terrestrial. In addition, the flytrap feeds primarily on arthropods like spiders, while the waterwheel lives off simple invertebrates, like certain types of plankton.

Điền vào số (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 33 to 37. 

All plants rely on nutrients taken from the soil in order to survive. However, in areas where the soil does not contain enough (33) _____ nutrients, some plants have adapted to supplement their diets from another source: living organisms. Though they are few in number, carnivorous plants are (34)_____ fascinating beings that “eat” anything from one-celled organisms to insects in order to survive. They are commonly found in marshlands. Carnivorous plants feature one of several types of “traps” to ensnare prey, which they consume to make up for nutrients that may be missing from the soil. While there are over 400 species of carnivorous plants in the world today, some are more prevalent than others.

The most well-known of these plants are the snap traps, which include the Venus flytrap. Snap traps are easily identified by their leaves, which are separated into two lobes that have the ability to fold together. Inside the lobes, the surface is covered with tiny hairs that are (35) _____ to movement. When the plant’s prey brushes against the hairs, it triggers a closing mechanism that rapidly brings the two lobes together, trapping the prey securely inside. The response of the traps is phenomenal (36)_____ speed: the time between triggering the hairs and snapping shut is less than a second. As the prey struggles inside the trap, it only triggers more hairs, causing the leaves to tighten their grip. The plant then secrets liquid chemicals from special glands into the trap to dissolve the prey and absorb all of its nutrients. Besides the Venus flytrap, only one other type of snap trap exists today, (37)_____ to as the waterwheel plant. The two share a common ancestor and differ only in a few ways. For instance, the waterwheel is an aquatic plant, while the flytrap is exclusively terrestrial. In addition, the flytrap feeds primarily on arthropods like spiders, while the waterwheel lives off simple invertebrates, like certain types of plankton.

Điền vào số (36)

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 33 to 37. 

All plants rely on nutrients taken from the soil in order to survive. However, in areas where the soil does not contain enough (33) _____ nutrients, some plants have adapted to supplement their diets from another source: living organisms. Though they are few in number, carnivorous plants are (34)_____ fascinating beings that “eat” anything from one-celled organisms to insects in order to survive. They are commonly found in marshlands. Carnivorous plants feature one of several types of “traps” to ensnare prey, which they consume to make up for nutrients that may be missing from the soil. While there are over 400 species of carnivorous plants in the world today, some are more prevalent than others.

The most well-known of these plants are the snap traps, which include the Venus flytrap. Snap traps are easily identified by their leaves, which are separated into two lobes that have the ability to fold together. Inside the lobes, the surface is covered with tiny hairs that are (35) _____ to movement. When the plant’s prey brushes against the hairs, it triggers a closing mechanism that rapidly brings the two lobes together, trapping the prey securely inside. The response of the traps is phenomenal (36)_____ speed: the time between triggering the hairs and snapping shut is less than a second. As the prey struggles inside the trap, it only triggers more hairs, causing the leaves to tighten their grip. The plant then secrets liquid chemicals from special glands into the trap to dissolve the prey and absorb all of its nutrients. Besides the Venus flytrap, only one other type of snap trap exists today, (37)_____ to as the waterwheel plant. The two share a common ancestor and differ only in a few ways. For instance, the waterwheel is an aquatic plant, while the flytrap is exclusively terrestrial. In addition, the flytrap feeds primarily on arthropods like spiders, while the waterwheel lives off simple invertebrates, like certain types of plankton.

Điền vào số (37)

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 from 38 to 42.

Our eyes and ears might be called transformers because they send the light and sound around us and turn them into electrical impulses that the brain can interpret. These electrical impulses that have been transformed by the eyes and ears reach the brain and are turned into massages that we can interpret. For the eye, the process begins as the eye admits light waves, bends them at the cornea and lens, and then focuses them on the retina. At the back of each eye, nerve fibers bundle together to form optic nerves, which join and then split into optic tracts. Some of the fibers cross so that part of the input from the right visual field goes into the left side of the brain, and vice versa. The process in the ear is carried out through sensory cells that are carried in fluid-filled canals and that are extremely sensitive to vibration. Sound that is transformed into electricity travels along nerve fibers in the auditory nerve. These fibers form a synapse with neurons that carry the massages to the auditory cortex on each side of the brain. 

According to the author, we might call our eyes and ears "transformers" because _____.

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 from 38 to 42.

Our eyes and ears might be called transformers because they send the light and sound around us and turn them into electrical impulses that the brain can interpret. These electrical impulses that have been transformed by the eyes and ears reach the brain and are turned into massages that we can interpret. For the eye, the process begins as the eye admits light waves, bends them at the cornea and lens, and then focuses them on the retina. At the back of each eye, nerve fibers bundle together to form optic nerves, which join and then split into optic tracts. Some of the fibers cross so that part of the input from the right visual field goes into the left side of the brain, and vice versa. The process in the ear is carried out through sensory cells that are carried in fluid-filled canals and that are extremely sensitive to vibration. Sound that is transformed into electricity travels along nerve fibers in the auditory nerve. These fibers form a synapse with neurons that carry the massages to the auditory cortex on each side of the brain. 

Which of the following is closest in meaning to the word “admits” in line 4?

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 from 38 to 42.

Our eyes and ears might be called transformers because they send the light and sound around us and turn them into electrical impulses that the brain can interpret. These electrical impulses that have been transformed by the eyes and ears reach the brain and are turned into massages that we can interpret. For the eye, the process begins as the eye admits light waves, bends them at the cornea and lens, and then focuses them on the retina. At the back of each eye, nerve fibers bundle together to form optic nerves, which join and then split into optic tracts. Some of the fibers cross so that part of the input from the right visual field goes into the left side of the brain, and vice versa. The process in the ear is carried out through sensory cells that are carried in fluid-filled canals and that are extremely sensitive to vibration. Sound that is transformed into electricity travels along nerve fibers in the auditory nerve. These fibers form a synapse with neurons that carry the massages to the auditory cortex on each side of the brain.

What does the word “them” in line 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 from 38 to 42.

Our eyes and ears might be called transformers because they send the light and sound around us and turn them into electrical impulses that the brain can interpret. These electrical impulses that have been transformed by the eyes and ears reach the brain and are turned into massages that we can interpret. For the eye, the process begins as the eye admits light waves, bends them at the cornea and lens, and then focuses them on the retina. At the back of each eye, nerve fibers bundle together to form optic nerves, which join and then split into optic tracts. Some of the fibers cross so that part of the input from the right visual field goes into the left side of the brain, and vice versa. The process in the ear is carried out through sensory cells that are carried in fluid-filled canals and that are extremely sensitive to vibration. Sound that is transformed into electricity travels along nerve fibers in the auditory nerve. These fibers form a synapse with neurons that carry the massages to the auditory cortex on each side of the brain.

According to the passage, when input from the right visual field goes into the left side of the brain, what happens?

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 from 38 to 42.

Our eyes and ears might be called transformers because they send the light and sound around us and turn them into electrical impulses that the brain can interpret. These electrical impulses that have been transformed by the eyes and ears reach the brain and are turned into massages that we can interpret. For the eye, the process begins as the eye admits light waves, bends them at the cornea and lens, and then focuses them on the retina. At the back of each eye, nerve fibers bundle together to form optic nerves, which join and then split into optic tracts. Some of the fibers cross so that part of the input from the right visual field goes into the left side of the brain, and vice versa. The process in the ear is carried out through sensory cells that are carried in fluid-filled canals and that are extremely sensitive to vibration. Sound that is transformed into electricity travels along nerve fibers in the auditory nerve. These fibers form a synapse with neurons that carry the massages to the auditory cortex on each side of the brain.

The phrase “carried out” could be best replaced by which of the following?

Read the following passage on transport, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

Alzheimer's disease impairs a person's ability to recall memories, both distant and as recent as a few hours before. Although there is not yet a cure for the illness, there may be hope for a cure with a protein called nerve growth factor. The protein is produced by nerve cells in the same region of the brain where Alzheimer's occurs. Based on this relationship, scientists from the University of Lund in Sweden and the University of California at San Diego designed an experiment to test whether doses of nerve growth factor could reverse the effects of memory loss caused by Alzheimer's. Using a group of rats with impaired memory, the scientists gave half of the rats doses of nerve growth factor while giving the other half a blood protein as a placebo, thus creating a control group. At the end of the four-week test, the rats given the nerve growth factor performed equally to rats with normal memory abilities. While the experiments do not show that nerve growth factor can stop the general process of deterioration caused by Alzheimer's, they do show potential as a means to slowing the process significantly.

With what topic is this passage mainly concerned?

Read the following passage on transport, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

Alzheimer's disease impairs a person's ability to recall memories, both distant and as recent as a few hours before. Although there is not yet a cure for the illness, there may be hope for a cure with a protein called nerve growth factor. The protein is produced by nerve cells in the same region of the brain where Alzheimer's occurs. Based on this relationship, scientists from the University of Lund in Sweden and the University of California at San Diego designed an experiment to test whether doses of nerve growth factor could reverse the effects of memory loss caused by Alzheimer's. Using a group of rats with impaired memory, the scientists gave half of the rats doses of nerve growth factor while giving the other half a blood protein as a placebo, thus creating a control group. At the end of the four-week test, the rats given the nerve growth factor performed equally to rats with normal memory abilities. While the experiments do not show that nerve growth factor can stop the general process of deterioration caused by Alzheimer's, they do show potential as a means to slowing the process significantly.

The word “impairs” in line 1 is most similar to which of the following?

Read the following passage on transport, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

Alzheimer's disease impairs a person's ability to recall memories, both distant and as recent as a few hours before. Although there is not yet a cure for the illness, there may be hope for a cure with a protein called nerve growth factor. The protein is produced by nerve cells in the same region of the brain where Alzheimer's occurs. Based on this relationship, scientists from the University of Lund in Sweden and the University of California at San Diego designed an experiment to test whether doses of nerve growth factor could reverse the effects of memory loss caused by Alzheimer's. Using a group of rats with impaired memory, the scientists gave half of the rats doses of nerve growth factor while giving the other half a blood protein as a placebo, thus creating a control group. At the end of the four-week test, the rats given the nerve growth factor performed equally to rats with normal memory abilities. While the experiments do not show that nerve growth factor can stop the general process of deterioration caused by Alzheimer's, they do show potential as a means to slowing the process significantly.

According to the passage, where is nerve growth factor produced in the body?

Read the following passage on transport, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

Alzheimer's disease impairs a person's ability to recall memories, both distant and as recent as a few hours before. Although there is not yet a cure for the illness, there may be hope for a cure with a protein called nerve growth factor. The protein is produced by nerve cells in the same region of the brain where Alzheimer's occurs. Based on this relationship, scientists from the University of Lund in Sweden and the University of California at San Diego designed an experiment to test whether doses of nerve growth factor could reverse the effects of memory loss caused by Alzheimer's. Using a group of rats with impaired memory, the scientists gave half of the rats doses of nerve growth factor while giving the other half a blood protein as a placebo, thus creating a control group. At the end of the four-week test, the rats given the nerve growth factor performed equally to rats with normal memory abilities. While the experiments do not show that nerve growth factor can stop the general process of deterioration caused by Alzheimer's, they do show potential as a means to slowing the process significantly.

Which of the following can be inferred from the passage?

Read the following passage on transport, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

Alzheimer's disease impairs a person's ability to recall memories, both distant and as recent as a few hours before. Although there is not yet a cure for the illness, there may be hope for a cure with a protein called nerve growth factor. The protein is produced by nerve cells in the same region of the brain where Alzheimer's occurs. Based on this relationship, scientists from the University of Lund in Sweden and the University of California at San Diego designed an experiment to test whether doses of nerve growth factor could reverse the effects of memory loss caused by Alzheimer's. Using a group of rats with impaired memory, the scientists gave half of the rats doses of nerve growth factor while giving the other half a blood protein as a placebo, thus creating a control group. At the end of the four-week test, the rats given the nerve growth factor performed equally to rats with normal memory abilities. While the experiments do not show that nerve growth factor can stop the general process of deterioration caused by Alzheimer's, they do show potential as a means to slowing the process significantly.

The passage most closely resembles which of the following patterns of organization?

Read the following passage on transport, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

Alzheimer's disease impairs a person's ability to recall memories, both distant and as recent as a few hours before. Although there is not yet a cure for the illness, there may be hope for a cure with a protein called nerve growth factor. The protein is produced by nerve cells in the same region of the brain where Alzheimer's occurs. Based on this relationship, scientists from the University of Lund in Sweden and the University of California at San Diego designed an experiment to test whether doses of nerve growth factor could reverse the effects of memory loss caused by Alzheimer's. Using a group of rats with impaired memory, the scientists gave half of the rats doses of nerve growth factor while giving the other half a blood protein as a placebo, thus creating a control group. At the end of the four-week test, the rats given the nerve growth factor performed equally to rats with normal memory abilities. While the experiments do not show that nerve growth factor can stop the general process of deterioration caused by Alzheimer's, they do show potential as a means to slowing the process significantly.

Which of the following is closest in meaning to the word "deterioration"?

Read the following passage on transport, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

Alzheimer's disease impairs a person's ability to recall memories, both distant and as recent as a few hours before. Although there is not yet a cure for the illness, there may be hope for a cure with a protein called nerve growth factor. The protein is produced by nerve cells in the same region of the brain where Alzheimer's occurs. Based on this relationship, scientists from the University of Lund in Sweden and the University of California at San Diego designed an experiment to test whether doses of nerve growth factor could reverse the effects of memory loss caused by Alzheimer's. Using a group of rats with impaired memory, the scientists gave half of the rats doses of nerve growth factor while giving the other half a blood protein as a placebo, thus creating a control group. At the end of the four-week test, the rats given the nerve growth factor performed equally to rats with normal memory abilities. While the experiments do not show that nerve growth factor can stop the general process of deterioration caused by Alzheimer's, they do show potential as a means to slowing the process significantly.

Which of the following could best replace the word "significantly"?

Read the following passage on transport, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 43 to 50.

Alzheimer's disease impairs a person's ability to recall memories, both distant and as recent as a few hours before. Although there is not yet a cure for the illness, there may be hope for a cure with a protein called nerve growth factor. The protein is produced by nerve cells in the same region of the brain where Alzheimer's occurs. Based on this relationship, scientists from the University of Lund in Sweden and the University of California at San Diego designed an experiment to test whether doses of nerve growth factor could reverse the effects of memory loss caused by Alzheimer's. Using a group of rats with impaired memory, the scientists gave half of the rats doses of nerve growth factor while giving the other half a blood protein as a placebo, thus creating a control group. At the end of the four-week test, the rats given the nerve growth factor performed equally to rats with normal memory abilities. While the experiments do not show that nerve growth factor can stop the general process of deterioration caused by Alzheimer's, they do show potential as a means to slowing the process significantly.

The relationship between nerve growth factor and a protein is similar to the relationship between Alzheimer's and ______.