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 a sound you will probably never hear, a sickened tree sending out a distress signal. But a group of scientists has heard the cries, and they think some insects also hear the trees and are drawn to them like vulture to a dying animal. Researchers with the US Department of Agriculture’s Forest Service fastened sensors to the bark of drought-stricken trees clearly heard distress calls. According to one of the scientists, most parched trees transmit their plight in the 50-hertz to 50kilohertz range. (The unaided human ear can detect no more than 20 kilohertz). Red oak, maple, white pine, and birch all make slightly different sounds in the form of vibrations at the surface of the wood.

   The scientists think that the vibrations are created when the water columns inside tubes that run along the length of the tree break, a result of too little water following through them.

   These fractured columns send out distinctive vibration patterns. Because some insects communicate at ultrasonic frequencies, they may pick up the trees' vibration and attack the weakened trees. Researchers are now running tests with potted trees that have been deprived of water to see if the sound is what attracts the insects. “Water-stressed trees also smell differently from other trees, and they experience thermal changes, so insects could be responding to something other than sound”, one scientist said.

Question: It can be inferred from the passage that research concerning the distress signals of trees______.

A. has been unproductive up to now

B. is no longer sponsored by the government

C. was conducted many years ago

D. is continuing

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 a sound you will probably never hear, a sickened tree sending out a distress signal. But a group of scientists has heard the cries, and they think some insects also hear the trees and are drawn to them like vulture to a dying animal. Researchers with the US Department of Agriculture’s Forest Service fastened sensors to the bark of drought-stricken trees clearly heard distress calls. According to one of the scientists, most parched trees transmit their plight in the 50-hertz to 50kilohertz range. (The unaided human ear can detect no more than 20 kilohertz). Red oak, maple, white pine, and birch all make slightly different sounds in the form of vibrations at the surface of the wood.

   The scientists think that the vibrations are created when the water columns inside tubes that run along the length of the tree break, a result of too little water following through them.

   These fractured columns send out distinctive vibration patterns. Because some insects communicate at ultrasonic frequencies, they may pick up the trees' vibration and attack the weakened trees. Researchers are now running tests with potted trees that have been deprived of water to see if the sound is what attracts the insects. “Water-stressed trees also smell differently from other trees, and they experience thermal changes, so insects could be responding to something other than sound”, one scientist said.

Question: Which of the following is the main topic of the passage?

A. The effect of insects on trees.

B. The vibrations produced by insects.

C. The mission of the U.S Forest Service.

D. The sounds made by trees.

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 a sound you will probably never hear, a sickened tree sending out a distress signal. But a group of scientists has heard the cries, and they think some insects also hear the trees and are drawn to them like vulture to a dying animal. Researchers with the US Department of Agriculture’s Forest Service fastened sensors to the bark of drought-stricken trees clearly heard distress calls. According to one of the scientists, most parched trees transmit their plight in the 50-hertz to 50kilohertz range. (The unaided human ear can detect no more than 20 kilohertz). Red oak, maple, white pine, and birch all make slightly different sounds in the form of vibrations at the surface of the wood.

   The scientists think that the vibrations are created when the water columns inside tubes that run along the length of the tree break, a result of too little water following through them.

   These fractured columns send out distinctive vibration patterns. Because some insects communicate at ultrasonic frequencies, they may pick up the trees' vibration and attack the weakened trees. Researchers are now running tests with potted trees that have been deprived of water to see if the sound is what attracts the insects. “Water-stressed trees also smell differently from other trees, and they experience thermal changes, so insects could be responding to something other than sound”, one scientist said.

Question: It can be inferred from the passage that research concerning the distress signals of trees______.Which of the following could be considered a cause of the distress signals of trees?

A. attacks by insects

B. experiments by scientists

C. torn roots

D. lack of water

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.

  Since water is the basis of life, composing the greater part of the tissues of all living things, the crucial problem of desert animals is to survive in a world where sources of flowing water are rare. And since man’s inexorable necessity is to absorb large quantities of water at frequent intervals, he can scarcely comprehend that many creatures of the desert pass their entire lives without a single drop.

   Uncompromising as it is, the desert has not eliminated life but only those forms unable to withstand its desiccating effects. No moist- skinned, water-loving animals can exist there. Few large animals are found. The giants of the North American desert are the deer, the coyote, and the bobcat. Since desert country is open, it holds more swift-footed running and leaping creatures than the tangled forest. Its population is largely nocturnal, silent, filled with reticence, and ruled by stealth. Yet they are not emaciated. Having adapted to their austere environment, they are as healthy as animals anywhere else in the word. The secret of their adjustment lies in the combination of behavior and physiology. None could survive if, like mad dogs and Englishmen, they went out in the midday sun; many would die in a matter of minutes. So most of them pass the burning hours asleep in cool, humid burrows underneath the ground, emerging to hunt only by night. The surface of the sun-baked desert averages around 150 degrees, but 18 inches down the temperature is only 60 degrees.

Question: The phrase “those forms” in the passage refers to all of the following EXCEPT

A. moist-skinned animals

B. many large animals

C. water-loving animals

D. the coyote and the bobcat

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.

  Since water is the basis of life, composing the greater part of the tissues of all living things, the crucial problem of desert animals is to survive in a world where sources of flowing water are rare. And since man’s inexorable necessity is to absorb large quantities of water at frequent intervals, he can scarcely comprehend that many creatures of the desert pass their entire lives without a single drop.

   Uncompromising as it is, the desert has not eliminated life but only those forms unable to withstand its desiccating effects. No moist- skinned, water-loving animals can exist there. Few large animals are found. The giants of the North American desert are the deer, the coyote, and the bobcat. Since desert country is open, it holds more swift-footed running and leaping creatures than the tangled forest. Its population is largely nocturnal, silent, filled with reticence, and ruled by stealth. Yet they are not emaciated. Having adapted to their austere environment, they are as healthy as animals anywhere else in the word. The secret of their adjustment lies in the combination of behavior and physiology. None could survive if, like mad dogs and Englishmen, they went out in the midday sun; many would die in a matter of minutes. So most of them pass the burning hours asleep in cool, humid burrows underneath the ground, emerging to hunt only by night. The surface of the sun-baked desert averages around 150 degrees, but 18 inches down the temperature is only 60 degrees.

Question: According to the passage, creatures in the desert

A. are smaller and fleeter than forest animals

B. are more active during the day than those in the tangled forest

C. live in an accommodating environment

D. are not as healthy as those anywhere else in the world

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.

  Since water is the basis of life, composing the greater part of the tissues of all living things, the crucial problem of desert animals is to survive in a world where sources of flowing water are rare. And since man’s inexorable necessity is to absorb large quantities of water at frequent intervals, he can scarcely comprehend that many creatures of the desert pass their entire lives without a single drop.

   Uncompromising as it is, the desert has not eliminated life but only those forms unable to withstand its desiccating effects. No moist- skinned, water-loving animals can exist there. Few large animals are found. The giants of the North American desert are the deer, the coyote, and the bobcat. Since desert country is open, it holds more swift-footed running and leaping creatures than the tangled forest. Its population is largely nocturnal, silent, filled with reticence, and ruled by stealth. Yet they are not emaciated. Having adapted to their austere environment, they are as healthy as animals anywhere else in the word. The secret of their adjustment lies in the combination of behavior and physiology. None could survive if, like mad dogs and Englishmen, they went out in the midday sun; many would die in a matter of minutes. So most of them pass the burning hours asleep in cool, humid burrows underneath the ground, emerging to hunt only by night. The surface of the sun-baked desert averages around 150 degrees, but 18 inches down the temperature is only 60 degrees.

Question: The author mentions all the following as examples of the behavior of desert animals EXCEPT

A. they are watchful and quiet

B. they sleep during the day

C. they dig home underground

D. they are noisy and aggressive

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.

  Since water is the basis of life, composing the greater part of the tissues of all living things, the crucial problem of desert animals is to survive in a world where sources of flowing water are rare. And since man’s inexorable necessity is to absorb large quantities of water at frequent intervals, he can scarcely comprehend that many creatures of the desert pass their entire lives without a single drop.

   Uncompromising as it is, the desert has not eliminated life but only those forms unable to withstand its desiccating effects. No moist- skinned, water-loving animals can exist there. Few large animals are found. The giants of the North American desert are the deer, the coyote, and the bobcat. Since desert country is open, it holds more swift-footed running and leaping creatures than the tangled forest. Its population is largely nocturnal, silent, filled with reticence, and ruled by stealth. Yet they are not emaciated. Having adapted to their austere environment, they are as healthy as animals anywhere else in the word. The secret of their adjustment lies in the combination of behavior and physiology. None could survive if, like mad dogs and Englishmen, they went out in the midday sun; many would die in a matter of minutes. So most of them pass the burning hours asleep in cool, humid burrows underneath the ground, emerging to hunt only by night. The surface of the sun-baked desert averages around 150 degrees, but 18 inches down the temperature is only 60 degrees.

Question: We can infer from the passage that

A. healthy animals live longer lives

B. living things adjust to their environment

C. desert life is colorful and diverse

D. water is the basis of desert life

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.

  Since water is the basis of life, composing the greater part of the tissues of all living things, the crucial problem of desert animals is to survive in a world where sources of flowing water are rare. And since man’s inexorable necessity is to absorb large quantities of water at frequent intervals, he can scarcely comprehend that many creatures of the desert pass their entire lives without a single drop.

   Uncompromising as it is, the desert has not eliminated life but only those forms unable to withstand its desiccating effects. No moist- skinned, water-loving animals can exist there. Few large animals are found. The giants of the North American desert are the deer, the coyote, and the bobcat. Since desert country is open, it holds more swift-footed running and leaping creatures than the tangled forest. Its population is largely nocturnal, silent, filled with reticence, and ruled by stealth. Yet they are not emaciated. Having adapted to their austere environment, they are as healthy as animals anywhere else in the word. The secret of their adjustment lies in the combination of behavior and physiology. None could survive if, like mad dogs and Englishmen, they went out in the midday sun; many would die in a matter of minutes. So most of them pass the burning hours asleep in cool, humid burrows underneath the ground, emerging to hunt only by night. The surface of the sun-baked desert averages around 150 degrees, but 18 inches down the temperature is only 60 degrees.

Question: The word “them” means

A. animal

B. minutes

C. people

D. water