Fill in the blanks:

Maybe you recycle cans, glass and paper. Do you know that nature recycles, too? One of the things nature (1)............ is water.Water goes from oceans, lakes and river into the air. Water falls from the air as (2)............ or snow. Rain and snow eventually find their way back to the ocean. Nature's recycling program for water is (3)............ the water cycle.

The water cycle has 4 stages: storage, evaporation, precipitation and runoff. Water on the Earth gets stored (4)............ oceans, lakes, rivers, ice and even underground. Water goes from storage into the atmosphere by a process called evaporation. When water evaporates, it changes from a liquid (5)............ a gas, called water vapor. Water vapor goes up into (6)............ atmosphere. Water returns to the Earth as precipitation in rain or snow by changing into drops of water (7)............ the air gets cold enough. Clouds are collections (8)............ water droplets. Most precipitation falls into the oceans and go right back into storage.

Water that falls on land always flows from (9)............ places to lower ones. This flow is called runoff. Water from land flows into streams. Streams join together to make (10)............ and eventually the water flows into storage in the oceans.

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.

What makes it rain? Rain falls from clouds for the same reason anything falls to Earth. The Earth’s gravity pulls it. But every cloud is made of water droplets or ice crystals. Why doesn’t rain or snow fall constantly from all clouds? The droplets or ice crystals in clouds are exceedingly small. The effect of gravity on them is minute. Air currents move and lift droplets so that the net downward displacement is zero, even though the droplets are in constant motion.

Droplets and ice crystals behave somewhat like dust in the air made visible in a shaft of sunlight. To the casual observer, dust seems to act in a totally random fashion moving about chaotically without fixed direction. But in fact dust particles are much larger than water droplets and they finally fall. The cloud droplet of average size is only 1/2500 inch in diameter. It is so small that it would take sixteen hours to fall half a mile in perfectly still air, and it does not fall out of moving air at all. Only when the droplet grows to a diameter of 1/125 inch or larger can it fall from the cloud. The average raindrop contains a million times as much water as a tiny cloud droplet. The growth of a cloud droplet to a size large enough to fall out is the cause of rain and other forms of precipitation. This important growth process is called “coalescence”.

What are water droplets?

A. They are ice crystals. 

B. They are small drops of dew.

C. They are watery fruits. 

D. They are animals living on ice.

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 28 to 34.

  Because the low latitudes of the Earth, the areas near the equator, receive more heat than the latitudes near the poles, and because the nature of heat is to expand and move, heat is transported from the tropics to the middle and high latitudes. Some of this heat is moved by winds and some by ocean currents, and some gets stored in the atmosphere in the form of latent heat. The term “latent heat” refers to the energy that has to be used to convert liquid water to water vapor. We know that if we warm a pan of water on a stove, it will evaporate, or turn into vapor, faster than if it is allowed to sit at room temperature. We also know that if we hang wet clothes outside in the summertime, they will dry faster than in winter, when the temperature is lower. The energy used in both cases to change liquid water to water vapor is supplied by heat - supplied by the stove in the first case and by the Sun in the latter case. This energy is not lost. It is stored as vapor in the atmosphere as latent heat. Eventually, the water stored as vapor in the atmosphere will condense to liquid again, and the energy will be released to the atmosphere.

          In the atmosphere, a large portion of the Sun’s incoming energy is used to evaporate water, primarily in the tropical oceans. Scientists have tried to quantify this proportion of the Sun’s energy. By analyzing temperature, water vapor, and wind data around the globe, they have estimated the quantity to be about 90 watts per square meter, or nearly 30 percent of the Sun’s energy. Once this latent heat is stored within the atmosphere, it can be transported, primarily to higher latitudes, by prevailing, large - scale winds. Or it can be transported vertically to higher levels in the atmosphere, where it forms clouds and subsequent storms, which then release the energy back to the atmosphere.

According to the passage, most ocean water evaporation occurs especially _________ .

A. around the higher latitudes

B. in the tropics

C. because of large - scale winds

D. because of strong ocean currents

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 28 to 34.

  Because the low latitudes of the Earth, the areas near the equator, receive more heat than the latitudes near the poles, and because the nature of heat is to expand and move, heat is transported from the tropics to the middle and high latitudes. Some of this heat is moved by winds and some by ocean currents, and some gets stored in the atmosphere in the form of latent heat. The term “latent heat” refers to the energy that has to be used to convert liquid water to water vapor. We know that if we warm a pan of water on a stove, it will evaporate, or turn into vapor, faster than if it is allowed to sit at room temperature. We also know that if we hang wet clothes outside in the summertime, they will dry faster than in winter, when the temperature is lower. The energy used in both cases to change liquid water to water vapor is supplied by heat - supplied by the stove in the first case and by the Sun in the latter case. This energy is not lost. It is stored as vapor in the atmosphere as latent heat. Eventually, the water stored as vapor in the atmosphere will condense to liquid again, and the energy will be released to the atmosphere.

          In the atmosphere, a large portion of the Sun’s incoming energy is used to evaporate water, primarily in the tropical oceans. Scientists have tried to quantify this proportion of the Sun’s energy. By analyzing temperature, water vapor, and wind data around the globe, they have estimated the quantity to be about 90 watts per square meter, or nearly 30 percent of the Sun’s energy. Once this latent heat is stored within the atmosphere, it can be transported, primarily to higher latitudes, by prevailing, large - scale winds. Or it can be transported vertically to higher levels in the atmosphere, where it forms clouds and subsequent storms, which then release the energy back to the atmosphere.

The underlined word “it” refers to _____ .

A. square meter

B. the Sun’s energy

C. latent heat

D. the atmosphere

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 28 to 34.

  Because the low latitudes of the Earth, the areas near the equator, receive more heat than the latitudes near the poles, and because the nature of heat is to expand and move, heat is transported from the tropics to the middle and high latitudes. Some of this heat is moved by winds and some by ocean currents, and some gets stored in the atmosphere in the form of latent heat. The term “latent heat” refers to the energy that has to be used to convert liquid water to water vapor. We know that if we warm a pan of water on a stove, it will evaporate, or turn into vapor, faster than if it is allowed to sit at room temperature. We also know that if we hang wet clothes outside in the summertime, they will dry faster than in winter, when the temperature is lower. The energy used in both cases to change liquid water to water vapor is supplied by heat - supplied by the stove in the first case and by the Sun in the latter case. This energy is not lost. It is stored as vapor in the atmosphere as latent heat. Eventually, the water stored as vapor in the atmosphere will condense to liquid again, and the energy will be released to the atmosphere.

          In the atmosphere, a large portion of the Sun’s incoming energy is used to evaporate water, primarily in the tropical oceans. Scientists have tried to quantify this proportion of the Sun’s energy. By analyzing temperature, water vapor, and wind data around the globe, they have estimated the quantity to be about 90 watts per square meter, or nearly 30 percent of the Sun’s energy. Once this latent heat is stored within the atmosphere, it can be transported, primarily to higher latitudes, by prevailing, large - scale winds. Or it can be transported vertically to higher levels in the atmosphere, where it forms clouds and subsequent storms, which then release the energy back to the atmosphere.

According to the passage, 30 percent of the Sun’s incoming energy _______

A. is stored in clouds in the lower latitudes

B. is transported by ocean currents

C. never leaves the upper atmosphere

D. gets stored as latent heat

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 28 to 34.

  Because the low latitudes of the Earth, the areas near the equator, receive more heat than the latitudes near the poles, and because the nature of heat is to expand and move, heat is transported from the tropics to the middle and high latitudes. Some of this heat is moved by winds and some by ocean currents, and some gets stored in the atmosphere in the form of latent heat. The term “latent heat” refers to the energy that has to be used to convert liquid water to water vapor. We know that if we warm a pan of water on a stove, it will evaporate, or turn into vapor, faster than if it is allowed to sit at room temperature. We also know that if we hang wet clothes outside in the summertime, they will dry faster than in winter, when the temperature is lower. The energy used in both cases to change liquid water to water vapor is supplied by heat - supplied by the stove in the first case and by the Sun in the latter case. This energy is not lost. It is stored as vapor in the atmosphere as latent heat. Eventually, the water stored as vapor in the atmosphere will condense to liquid again, and the energy will be released to the atmosphere.

          In the atmosphere, a large portion of the Sun’s incoming energy is used to evaporate water, primarily in the tropical oceans. Scientists have tried to quantify this proportion of the Sun’s energy. By analyzing temperature, water vapor, and wind data around the globe, they have estimated the quantity to be about 90 watts per square meter, or nearly 30 percent of the Sun’s energy. Once this latent heat is stored within the atmosphere, it can be transported, primarily to higher latitudes, by prevailing, large - scale winds. Or it can be transported vertically to higher levels in the atmosphere, where it forms clouds and subsequent storms, which then release the energy back to the atmosphere.

The word “convert” is closest in meaning to ________ .

A. mix       

B. change    

C. adapt      

D. reduce

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 28 to 34.

  Because the low latitudes of the Earth, the areas near the equator, receive more heat than the latitudes near the poles, and because the nature of heat is to expand and move, heat is transported from the tropics to the middle and high latitudes. Some of this heat is moved by winds and some by ocean currents, and some gets stored in the atmosphere in the form of latent heat. The term “latent heat” refers to the energy that has to be used to convert liquid water to water vapor. We know that if we warm a pan of water on a stove, it will evaporate, or turn into vapor, faster than if it is allowed to sit at room temperature. We also know that if we hang wet clothes outside in the summertime, they will dry faster than in winter, when the temperature is lower. The energy used in both cases to change liquid water to water vapor is supplied by heat - supplied by the stove in the first case and by the Sun in the latter case. This energy is not lost. It is stored as vapor in the atmosphere as latent heat. Eventually, the water stored as vapor in the atmosphere will condense to liquid again, and the energy will be released to the atmosphere.

          In the atmosphere, a large portion of the Sun’s incoming energy is used to evaporate water, primarily in the tropical oceans. Scientists have tried to quantify this proportion of the Sun’s energy. By analyzing temperature, water vapor, and wind data around the globe, they have estimated the quantity to be about 90 watts per square meter, or nearly 30 percent of the Sun’s energy. Once this latent heat is stored within the atmosphere, it can be transported, primarily to higher latitudes, by prevailing, large - scale winds. Or it can be transported vertically to higher levels in the atmosphere, where it forms clouds and subsequent storms, which then release the energy back to the atmosphere.

Why does the author mention “the stove” in the passage?

A. To describe the heat of the Sun.

B. To illustrate how water vapor is stored.

C. To show how energy is stored.

D. To give an example of a heat source.

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 28 to 34.

  Because the low latitudes of the Earth, the areas near the equator, receive more heat than the latitudes near the poles, and because the nature of heat is to expand and move, heat is transported from the tropics to the middle and high latitudes. Some of this heat is moved by winds and some by ocean currents, and some gets stored in the atmosphere in the form of latent heat. The term “latent heat” refers to the energy that has to be used to convert liquid water to water vapor. We know that if we warm a pan of water on a stove, it will evaporate, or turn into vapor, faster than if it is allowed to sit at room temperature. We also know that if we hang wet clothes outside in the summertime, they will dry faster than in winter, when the temperature is lower. The energy used in both cases to change liquid water to water vapor is supplied by heat - supplied by the stove in the first case and by the Sun in the latter case. This energy is not lost. It is stored as vapor in the atmosphere as latent heat. Eventually, the water stored as vapor in the atmosphere will condense to liquid again, and the energy will be released to the atmosphere.

          In the atmosphere, a large portion of the Sun’s incoming energy is used to evaporate water, primarily in the tropical oceans. Scientists have tried to quantify this proportion of the Sun’s energy. By analyzing temperature, water vapor, and wind data around the globe, they have estimated the quantity to be about 90 watts per square meter, or nearly 30 percent of the Sun’s energy. Once this latent heat is stored within the atmosphere, it can be transported, primarily to higher latitudes, by prevailing, large - scale winds. Or it can be transported vertically to higher levels in the atmosphere, where it forms clouds and subsequent storms, which then release the energy back to the atmosphere.

The passage mainly discusses how heat __________

A. is transformed and transported in the Earth’s atmosphere.

B. is transported by ocean currents.

C. can be measured and analyzed by scientists.

D. moves about the Earth’s equator.

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.

What makes it rain? Rain falls from clouds for the same reason anything falls to Earth. The Earth’s gravity pulls it. But every cloud is made of water droplets or ice crystals. Why doesn’t rain or snow fall constantly from all clouds? The droplets or ice crystals in clouds are exceedingly small. The effect of gravity on them is minute. Air currents move and lift droplets so that the net downward displacement is zero, even though the droplets are in constant motion.

Droplets and ice crystals behave somewhat like dust in the air made visible in a shaft of sunlight. To the casual observer, dust seems to act in a totally random fashion moving about chaotically without fixed direction. But in fact dust particles are much larger than water droplets and they finally fall. The cloud droplet of average size is only 1/2500 inch in diameter. It is so small that it would take sixteen hours to fall half a mile in perfectly still air, and it does not fall out of moving air at all. Only when the droplet grows to a diameter of 1/125 inch or larger can it fall from the cloud. The average raindrop contains a million times as much water as a tiny cloud droplet. The growth of a cloud droplet to a size large enough to fall out is the cause of rain and other forms of precipitation. This important growth process is called “coalescence”.

What is the diameter of the average cloud droplet?

A. 1/16 inch 

B. 1/125 inch

C. 1/2500 inch 

D. one millionth of an inch