A straight line is distance between two points. [ ] A．the shortest B．shortest C．shorter 题目和参考答案——青夏教育精英家教网—

What do you do if you're stranded（处于困境的）on a lonely island? Surely you need to find a way to get in touch with the outside world. Your best chance of doing this is to draw the attention of a passing plane.
　　Body signals（信号）
　　Pilots from different countries understand body signals if they have the correct training. When you wave your arms up and down in a straight line, it means "yes". When you point downwards and swing your arm from side to side, it means "no". If you want the pilot to know that it's safe to land, push your hands out in front of you and bend（弯曲）your knees. If you want to say that it's not safe to land, put your arms in the air and move them to one side.
　　Smoke signals
　　The smoke from a fire can be seen from far away, so it's a good way to draw attention. If the weather is dry, it isn't hard to start a fire. Remember, however, that fires can be very dangerous if they get out of control. Never light a fire unless you're sure that it can't spread. If the ground is dark, light smoke can be seen more easily. Green grass and leaves produce light smoke.
　　Ground-to-air signals
　　It's a good idea to build some signals, too. Use large pieces of wood to make the symbols(标记). If you can't find any wood, use earth. Some useful symbols are:
　　F "I need food and water."
　　II "I need medicine."
　　I "I am badly hurt."
　　X" I am unable to move from here."
　　Pilots' replies
　　If the pilot lowers the plane's wings from side to side, this means "message received and understood". (At night, the pilot flashes the plane's green lights.) If the pilots flies the plane in a clockwise circle, this means "message received but not understood".(At night, the pilot flashes the plane's red lights.)
However, there is no signal which means "message not received". Why not?
【小题1】 Which picture means "it's not safe land"?

　
【小题2】 What can we learn from the passage?

A．Swinging your arm from side to side means "yes".

B．If the ground is dark, light smoke can't be seen.

C．If you need some medicine, make a symbol "II".

D．The pilots make replies with a blue light at night.

　　【小题3】 What is the passage mainly about?

A．The explanation of building signals on an island.

B．The importance of making signals on an island.

C．Ways of sending out signals on a lonely island.

D．Ways of receiving signals from a lonely island

What do you do if you're stranded（处于困境的）on a lonely island? Surely you need to find a way to get in touch with the outside world. Your best chance of doing this is to draw the attention of a passing plane.
　　Body signals（信号）
　　Pilots from different countries understand body signals if they have the correct training. When you wave your arms up and down in a straight line, it means "yes". When you point downwards and swing your arm from side to side, it means "no". If you want the pilot to know that it's safe to land, push your hands out in front of you and bend（弯曲）your knees. If you want to say that it's not safe to land, put your arms in the air and move them to one side.
　　Smoke signals
　　The smoke from a fire can be seen from far away, so it's a good way to draw attention. If the weather is dry, it isn't hard to start a fire. Remember, however, that fires can be very dangerous if they get out of control. Never light a fire unless you're sure that it can't spread. If the ground is dark, light smoke can be seen more easily. Green grass and leaves produce light smoke.
　　Ground-to-air signals
　　It's a good idea to build some signals, too. Use large pieces of wood to make the symbols(标记). If you can't find any wood, use earth. Some useful symbols are:
　　F "I need food and water."
　　II "I need medicine."
　　I "I am badly hurt."
　　X" I am unable to move from here."
　　Pilots' replies
　　If the pilot lowers the plane's wings from side to side, this means "message received and understood". (At night, the pilot flashes the plane's green lights.) If the pilots flies the plane in a clockwise circle, this means "message received but not understood".(At night, the pilot flashes the plane's red lights.)
However, there is no signal which means "message not received". Why not?
【小题1】 Which picture means "it's not safe land"?

　
【小题2】 What can we learn from the passage?

A．Swinging your arm from side to side means "yes".

B．If the ground is dark, light smoke can't be seen.

C．If you need some medicine, make a symbol "II".

D．The pilots make replies with a blue light at night.

　　【小题3】 What is the passage mainly about?

A．The explanation of building signals on an island.

B．The importance of making signals on an island.

C．Ways of sending out signals on a lonely island.

D．Ways of receiving signals from a lonely island

A recent survey of 2000 parents in Britain showed that they are often afraid of science questions asked by their curious children only because they have no idea what the answer is. Here is a list of some simple questions that you can ask your parents to see if they know the answers.

Q: Why is the sky blue?

A: You probably know white sunlight is made up of seven colors. While it moves in a straight line when going through space, it starts to divide as it hits “raised area” in the atmosphere. The ones with longest wavelengths pass through easily. The blue , however , can be taken in by the gas molecules (分子) because it has a shorter wavelength , which in turn scatters (使分散) it in different directions. That’s why when you look up at the sky, it appears to be blue.

Q:Why does the moon sometimes appear during the daytime?

A: The simple answer to that is because just like any other object it is being lit by the sun. As long as it is around 45 degrees or even 90 degrees off the sun, it will receive light and be able to be seen. The only time it is not able to be seen during its 28-day orbit (轨道) around the earth is when it is right between the earth and the sun. That’s because its back , which is not lit by the sun, is facing us.

Q: Where do birds/ honeybees go in winter?

A: While the bird part is quite easy, since a lot of them get together and travel, the honeybee part is likely to puzzle your parents. It turns out that these busy insects stop being that active when the temperature drops below 50°F. Instead ,they get together in the lower central area of the hive （蜂巢）and form a ball around their queen. This helps keep both warm enough to survive the cold winter months.

1.The sky looks blue mainly because the color blue in the sunlight_______.

A. has the longest wavelength among all the colors

B. cannot be taken in by the gas molecules

C. doesn’t hit “raised area” in the atmosphere

D. cannot pass through space successfully

2.How long can’t the moon be seen during the daytime in a month?

A. 2 B. 28 C.30 D. 31

3.What do honeybees choose to do when the temperature drops below 50°F?

A. They choose to be active in the wild.

B. They choose to keep themselves warm.

C. They choose to travel to a warm place.

D. They choose to get together in the upper central area of the hive.

4.What is NOT explained in the passage?

A. Why is the sky blue?

B. Why is the moon able to be seen during the daytime?

C. Why do birds travel in winter?

D. Where do honeybees go in winter?

Have you ever wondered?

1. Why do airplanes take longer to fly west than east?

It can take five hours to go west-east from New York (NY) to London but seven hours to travel east-west from London to NY. The reason for the difference is an atmospheric phenomenon known as the jet (喷射) stream. The jet stream is a very high altitude wind which always blows from the west to the east across the Atlantic. The planes moving at a constant air speed thus go faster in the west-east direction when they are moving with the wind than in the opposite direction.

2. What would happen if the gravity on Earth was suddenly turned off?

Supposing we could magically turn off gravity. Would buildings and other structures (建筑物) float away? What happened would depend on how strongly the things were attached to the Earth. The Earth is moving at quite a speed, moving at over a thousand miles per hour. If you turn something around your head on a string (细绳), it goes around in a circle until you let go of the string. Then it flies off in a straight line. ‘Switching off’ gravity would be like letting go of the string. Things not attached to the Earth would fly off in a straight line. People in buildings would suddenly shoot upwards at a great speed until they hit the ceiling. Most things outside would fly off into space.

1.What information can we get from the first passage?

A．It is the jet stream that affects how fast airplanes fly.

B．Planes go slower when they are moving with the wind.

C．It takes more time to fly from NY to London than from London to NY.

D．The jet stream always blows from the east to the west across the Atlantic.

2.The word “shoot” underlined in the 2nd passage probably means “__________”.

A．send for B．move quickly

C．come out D．grow quickly

3.It can be inferred that without gravity __________.

A．buildings and other structures would float away

B．trees and buildings would not so easily fly off

C．something around your head would not float away

D．everything outside buildings would fly off into space

4.Which of the following statements is not mentioned in the passage?

A．It takes seven hours to travel from London to New York.

B．The earth is moving at a high speed

C．Everything on the earth will float away if there’s no gravity.

D．Everything not attached to the earth would fly off in a straight line.

5.Where can we most probably read this text?

A．In a research paper.

B．In a short story.

C．In a travel magazine.

D．In a student’s book.

Have you ever wondered?

1. Why do airplanes take longer to fly west than east?

It can take five hours to go west-east from New York (NY) to London but seven hours to travel east-west from London to NY. The reason for the difference is an atmospheric phenomenon (大气现象) known as the jet stream (气流). The jet stream is a very high altitude (=" above" sea level) wind which always blows from the west to the east across the Atlantic. So the planes moving at a constant air speed go faster from the west to the east when they are moving with the wind than in the opposite.

2. What would happen if the gravity on Earth was suddenly turned off?

Supposing we could magically turn off gravity. Would buildings and other structures（建筑物）float away? What happened would depend on (依靠) how strongly the things were attached (吸附) to the earth. The earth is moving at quite a speed, moving at over a thousand miles per hour. If you turn something around your head on a string, it goes around in a circle until you let go of the string. Then it flies off in a straight line. ‘Turning off’ gravity would be like letting go of the string. Things not attached to the earth would fly off in a straight line. People in buildings would suddenly shoot upwards at a great speed until they hit the ceiling (=" top" surface of a room). Most things outside would fly off into space.

1.What information can we get from the first passage?

A．It is the jet stream that affects how fast airplanes fly.

B．Planes go slower when they are moving with the wind.

C．It takes more time to fly from NY to London than from London to NY.

D．The jet stream always blows from the east to the west across the Atlantic.

2.The underlined word “shoot” in the 2nd paragraph means “_________”.

A．send for

B．move quickly

C．come out

D．grow quickly

3.It can be known that without gravity _________.

A．buildings and other structures would float away

B．trees and buildings would not so easily fly off

C．something around your head would not float away

D．everything outside buildings would fly off into space

4.Where can we read this passage?

A．In a research paper.	B．In a short story.
C．In a travel magazine.	D．In a student’s book

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