改错
Where doesyour cousin live on?                        (　　)?   
A      B                   C

Trees are useful to man in three very important ways. The first important way is that they provide man with food, wood and other products. Trees provide not only man with food, but also many animals with food. Without trees many animals could not live on the earth. It’s not easy for man to live on the earth, either.

The second important way is that trees give us shade. On a hot summer day, people are eager(渴望)to have a rest under the shade of a tree after they have walked a long way. You can imagine how important the shade of a tree is to man and to animals.

The third important way is that trees help to prevent drought and foods. However, in many parts of the world, man has not realized the third important way. He has cut trees down in large numbers. In the end he finds that he has lost the best friends he had.

What are you going to do if you are in a burning house？ How will you escape？ Do you know how to save yourself？ Please read the following passage.

   Escaping a fire is a serious matter. Knowing what to do during a fire can save you life. It is important to know the ways you can use and show them to everyone in the family， such as stairways and fire escapes， but not lifts.

　　From the lower floors of the buildings， escaping through windows is possible， learn the best way of leaving by windows with the least chance of serious injury.

　　The second floor window is usually not very high from the ground. An average person， hanging by the finger-tips will have a drop of about six feet to the ground. It is about the height of an average man. Of course， it is safer to jump a short way than to stay in a burning building.

　　Windows are also useful when you are waiting for help. Be sure to keep the door closed. Or smoke and fire may be drawn into the room. Keep your head low at the window to be sure you get fresh air rather than smoke that may leaked（渗） into the room.

　　On a second or third floor， the best windows for escape are those that open onto a roof. From the roof a person can drop to the ground more safely. Dropping onto cement（水泥） might end in injury. Bushes（灌木丛） and grass can help to break a fall.

1.It is important to _______.

A. put out the fire in the burning house     B. know the ways to escape the fire

C. jump off a burning house                       D. keep the door closed

2.It is possible to escape through the windows _______.

A. if there are some bushes on the ground        

B. if you are strong enough

C. if you live on a lower floor                  

D. If you have a long rope

3.Which of the following escaping way is NOT right？ _______.

A. You can escape though stairways.       

B. You can choose fire escapes.

C. Escape from the windows that open onto a roof.     

D. Use a lift to come down at once.

4.Open the window so that _______ if the building is on fire.

A. you can get fresh air                           B. you can call for help

C. you can easily jump off                        D. you can be seen first

5.The best title of the passage is _______.

A. Escaping from the Windows       

B. Save Yourself in the Burning House

C. Knowledge on Fire                    

D. Waiting for Help

What is the sky？ Where is it？ How bright is it？ What lies above it？ These questions are difficult to answer, aren’t they？

　　Is the sky blue？ The sky has no color. We know that there is air around the world. When planes fly, they need air to lift their wings. Planes can’t fly very high because the air gets thinner when they go up higher. If we go up about 1,200 kilometers from the earth, we’ll find no air there.

　　When we talk about the sky, we usually mean the atmosphere around the earth. It is like a very thick “cover” over the earth and keeps it warm. Without the “cover”, the earth would be a very cold place and nothing could live on it.

　　Looking up above us, you will see the blue sky with white clouds. It is usually light blue, but the sky would be dark blue if you go to the top of the highest mountains. And you will see fewer clouds between you and the sun.

　　And if you sit in a spaceship high above the earth, there is no air at all. The sky would be so dark that its color would be black.

　　Sometimes the sky doesn’t look blue. When the sun rises and falls, you will see red, orange, and other colors in the sky. These are the most beautiful moments of the day.

　　Now you may understand that we see colors because the air scatters (散射) the sunlight. Light travels through the air. Without air, there would be no light and no colors.

1.Planes can’t fly very high because ____________.

A．there is air around the world

B．the air gets thinner when they go up higher

C．it’s warmer in the sky

D．the air gets thicker when they go up higher

2.We can see colors of the sky because ____________.

A．the sun rises and falls every day

B．the sky has lots of colors

C．the air scatters the sunlight

D．the sunlight has many colors

3.Which of the following is TRUE？

A．There is little air without light and colors in the sky.

B．The sky will look red, orange and other colors at noon.

C．The sky has only one color when the sun rises and falls.

D．The sky is dark blue if you go to the top of the highest mountains.