单选题The very first air passengers in the balloon were _____.A the King and the QueenB two FrenchmenC two animalsD the Montgolfiers

共用题干
Please Fasten Your Seatbelts
Severe turbulence（湍流）can kill aircraft passengers. Now,in test flights over the Rocky
Mountains , NASA（美国航空航天局）engineers have successfully detected clear-air turbulence up to 10 seconds before an aircraft hits it.
Clear-air turbulence often catches pilots by surprise.Invisible to radar,it is difficult to forecast and can hurl（用力抛出去）passengers about the cabin. In December 1 997 , one passenger died and a hundred others were injured when unexpected rough air caused a United Airlines flight over the Pacific to drop 300 meters in a few seconds.
However,passengers can avoid serious injury by fastening their seatbelts.“It is the only antidote（对策）for this sort of thing,”says Rod Bogue,project manager at NASA's Dryden Flight
Research Center in Edwards,California.
The centre's new turbulence detector is based on lidar,or laser radar. Laser pulses are sent ahead of the plane and these are then reflected back by particles in the air. The technique depends on the Doppler effect.The wavelength of the light shifts according to the speed at which the particles are approaching. In calm air,the speed equals the plane's airspeed.But as the particles swirl（打漩）in rough air,their speed of approach increases or decreases rapidly .The rate of change in speed corresponds to the severity（激烈程度）of the turbulence.
In a series of tests that began last month,a research jet flew repeatedly into disturbed air over the mountain ridges（山脉）near Pueblo , Colorado. The lidar detector spotted turbulence between 3 and 8 kilometers ahead,and its forecasts of strength and duration corresponded closely with the turbulence that the plane encountered.
Bogue says that he had“a comfortable amount of time”to fasten his seatbelt. The researchers are planning to improve the lidar's range with a more powerful beam.The system could be installed on commercial aircraft in the next few years.

What does“clear-air turbulence”in Paragraph 1 probably mean?
A: A not very rough storm.
B: Unexpected disturbed air.
C: A kind of visible storm.
D: A storm over mountain ridges.

共用题干
Rockets in the Sky
If someone asked you,"What color is the sky?"I expect that you would answer,"Blue."I am afraid that you would be wrong.The sky has no color.When we see blue,we are looking at blue sunlight.The sunlight is shining on little bits of dust in the air.
We know that there is air all around the world.We could not breathe without air.Airplanes could not fly without air.They need air to lift their wings.Airplanes cannot fly very high because as they go higher the air gets thinner.If we go far enough away from the earth,we find there is no air.
What is the sky?The sky is space.In this space there is nothing except the sun,the moon and all the stars. Scientists have always wanted to know more about the other worlds in the space.They have looked at them through telescopes and in this way they have found out a great deal.The moon is about 384 ,000 kilometers away from the earth.An airplane cann't fly to the moon but there is a thing that can fly even when there is no air. This is rocket.
I am sure that you are asking,"How does a rocket fly?"If you want to know,get a balloon and then blow it up until it is quite big.Do not tie up the neck of the balloon.Let go!The balloon will fly off through the air very quickly.The air inside the balloon tries to get out.It rushes out through the neck of the balloon and this pushes the balloon through the air.It does not need wings like an airplane.
This is how a rocket works.It is not made of rubber（橡胶）like a balloon,of course.It is made of metal. The metal must not be heavy but it must be very strong.There is gas inside the rocket which is made very hot. When it rushes out of the end of the rocket,the rocket is pushed up into the air.
Rockets can fly far out into space.Rockets with men inside them have already reached the moon.Several rockets,without men inside them,have been sent to other worlds much farther away.One day rockets may be able to go anywhere in the space.

When an airplane flies too high,______.
A:the air will be too thin to support its wings
B:the air will become thicker
C:the air will exert pressure on it
D:the air will disappear in no time

共用题干
Rockets in the Sky
If someone asked you,"What color is the sky?"I expect that you would answer,"Blue."I am afraid that you would be wrong.The sky has no color.When we see blue,we are looking at blue sunlight.The sunlight is shining on little bits of dust in the air.
We know that there is air all around the world.We could not breathe without air.Airplanes could not fly without air.They need air to lift their wings.Airplanes cannot fly very high because as they go higher the air gets thinner.If we go far enough away from the earth,we find there is no air.
What is the sky?The sky is space.In this space there is nothing except the sun,the moon and all the stars. Scientists have always wanted to know more about the other worlds in the space.They have looked at them through telescopes and in this way they have found out a great deal.The moon is about 384 ,000 kilometers away from the earth.An airplane cann't fly to the moon but there is a thing that can fly even when there is no air. This is rocket.
I am sure that you are asking,"How does a rocket fly?"If you want to know,get a balloon and then blow it up until it is quite big.Do not tie up the neck of the balloon.Let go!The balloon will fly off through the air very quickly.The air inside the balloon tries to get out.It rushes out through the neck of the balloon and this pushes the balloon through the air.It does not need wings like an airplane.
This is how a rocket works.It is not made of rubber（橡胶）like a balloon,of course.It is made of metal. The metal must not be heavy but it must be very strong.There is gas inside the rocket which is made very hot. When it rushes out of the end of the rocket,the rocket is pushed up into the air.
Rockets can fly far out into space.Rockets with men inside them have already reached the moon.Several rockets,without men inside them,have been sent to other worlds much farther away.One day rockets may be able to go anywhere in the space.

A rocket can fly to the moon because______.
A:it looks like a balloon
B:it is much lighter than an airplane
C:it doesn't have wings
D:it works like an untied balloon

共用题干
Please Fasten Your Seatbelts
Severe turbulence（湍流）can kill aircraft passengers.Now,in test flights over the Rocky Mountains, NASA（美国航空航天局）engineers have successfully detected clear-air turbulence up to 10 seconds before an aircraft hits it.
Clear-air turbulence often catches pilots by surprise.Invisible to radar,it is difficult to forecast and can hurl（用力抛出去）passengers about the cabin.In December 1997 , one passenger died and a hundred others were injured when unexpected rough air caused a United Airlines flight over the Pacific to drop 300 meters in a few seconds.
However,passengers can avoid serious injury by fastening their seatbelts."It is the only antidote（对 策）for this sort of thing,"says Rod Bogue, project manager at NASA's Dryden Flight Research Center in Edwards,California.
The Center's new turbulence detector is based on lidar,or laser-radar.Laser pulses are sent ahead of the plane and these are then reflected back by particles in the air.The technique depends on the Doppler Effect（多普勒效应）.The wavelength of the light shifts according to the speed at which the particles are approaching.In calm air,the speed equals the plane's airspeed.But as the particles swirl（打漩） in rough air,their speed of approach increases or decreases rapidly.The rate of change in speed corresponds to the severity（激烈程度）of the turbulence.
In a series of tests that began last month,a research jet flew repeatedly into、 disturbed air over the mountain ridges（山脉）near Pueblo , Colorado.The lidar detector spotted turbulence between 3 and 8 kilometers ahead, and its forecasts of strength and duration corresponded closely with the turbulence that the plane encountered.
Bogue says that he had"a comfortable amount of time"to fasten his seatbelt.The researchers are planning to improve the lidar's range with a more powerful beam.The system could be installed on commercial aircraft in the next few years.

What does"clear-air turbulence"in Paragraph 1 probably mean?
A:A not very rough storm.
B:Unexpected disturbed air.
C:A kind of visible storm.
D:A storm over mountain ridges.

When television first began to expand,very few of the people who had becom commentators were able to be equally effective on television.Some of the experienced when they were trying to（ ）technical.

A.turn
B.adapt
C.alter
D.modify

共用题干
Rockets in the Sky
If someone asked you,"What color is the sky?"I expect that you would answer,"Blue."I am afraid that you would be wrong.The sky has no color.When we see blue,we are looking at blue sunlight.The sunlight is shining on little bits of dust in the air.
We know that there is air all around the world.We could not breathe without air.Airplanes could not fly without air.They need air to lift their wings.Airplanes cannot fly very high because as they go higher the air gets thinner.If we go far enough away from the earth,we find there is no air.
What is the sky?The sky is space.In this space there is nothing except the sun,the moon and all the stars. Scientists have always wanted to know more about the other worlds in the space.They have looked at them through telescopes and in this way they have found out a great deal.The moon is about 384 ,000 kilometers away from the earth.An airplane cann't fly to the moon but there is a thing that can fly even when there is no air. This is rocket.
I am sure that you are asking,"How does a rocket fly?"If you want to know,get a balloon and then blow it up until it is quite big.Do not tie up the neck of the balloon.Let go!The balloon will fly off through the air very quickly.The air inside the balloon tries to get out.It rushes out through the neck of the balloon and this pushes the balloon through the air.It does not need wings like an airplane.
This is how a rocket works.It is not made of rubber（橡胶）like a balloon,of course.It is made of metal. The metal must not be heavy but it must be very strong.There is gas inside the rocket which is made very hot. When it rushes out of the end of the rocket,the rocket is pushed up into the air.
Rockets can fly far out into space.Rockets with men inside them have already reached the moon.Several rockets,without men inside them,have been sent to other worlds much farther away.One day rockets may be able to go anywhere in the space.

Which of the following statements about a rocket is NOT true?
A:It can fly when there is no air.
B:It can fly without wings.
C:It is made of strong metal.
D:It is propelled by burning gas inside it.

共用题干
Rockets in the Sky
If someone asked you,"What color is the sky?"I expect that you would answer,"Blue."I am afraid that you would be wrong.The sky has no color.When we see blue,we are looking at blue sunlight.The sunlight is shining on little bits of dust in the air.
We know that there is air all around the world.We could not breathe without air.Airplanes could not fly without air.They need air to lift their wings.Airplanes cannot fly very high because as they go higher the air gets thinner.If we go far enough away from the earth,we find there is no air.
What is the sky?The sky is space.In this space there is nothing except the sun,the moon and all the stars. Scientists have always wanted to know more about the other worlds in the space.They have looked at them through telescopes and in this way they have found out a great deal.The moon is about 384 ,000 kilometers away from the earth.An airplane cann't fly to the moon but there is a thing that can fly even when there is no air. This is rocket.
I am sure that you are asking,"How does a rocket fly?"If you want to know,get a balloon and then blow it up until it is quite big.Do not tie up the neck of the balloon.Let go!The balloon will fly off through the air very quickly.The air inside the balloon tries to get out.It rushes out through the neck of the balloon and this pushes the balloon through the air.It does not need wings like an airplane.
This is how a rocket works.It is not made of rubber（橡胶）like a balloon,of course.It is made of metal. The metal must not be heavy but it must be very strong.There is gas inside the rocket which is made very hot. When it rushes out of the end of the rocket,the rocket is pushed up into the air.
Rockets can fly far out into space.Rockets with men inside them have already reached the moon.Several rockets,without men inside them,have been sent to other worlds much farther away.One day rockets may be able to go anywhere in the space.

What color is the sky?
A:It is blue.
B:It is white.
C:It is grey.
D:It has no color.