Things similar continuously happened in Haiti and Chile.Thousands of people were

buried in the earthquake and lost their fives.What if we could have warned them? People are always trying hard to find a way of preventing building collapsing(坍塌).Better materials and technology help,but are not a solution.Just like humans,a building has its own life circle from  “birth” to “death”.If we know when a building is going to collapse,we can repair it in advance or get out before it falls.

    Now, scientists at the University of Illinois have developed a material that turns red before it breaks.The invention could be used in things like climbing ropes,or bridge supports.The secret behind the color-changing material is a type of molecule(分子).A molecule is a group of atoms held together by chemical bonds(化学键).Imagine you and your friends standing in a circle,holding hands.Each person stands for one atom,your hands represent the bonds,and the entire circle represents a molecule.If one person lets go of his or her hands,the molecule changes color.The research team put the molecule into a soft material.When the researchers stretched(拉长) the material:it turned bright red a few seconds before it broke into two pieces.

When they repeatedly stretched and relaxed the material,without breaking it,it only turned a little red.

The major problem is,light can get rid of the red color.When the team shone a bright light on the molecule,the broken bond was fixed,and the color disappeared.If bright fight keeps the red color from appearing,the material’s warning system will be useless.Scientists still have a lot of work to do before the color-changing molecule can be used outside the lab.

The passage mainly about

A. a way of preventing building from breaking down

B. a series of earthquakes in Haiti and Chile

C. a way of warning before buildings collapse

D. a newly-discovered structure of a molecule

According to the passage,we can conclude that

A.there are problems to solve before putting the new material to use

B.scientists have found the life circle of buildings from “birth” to “death”

C.bright fight makes the red color visible to human eyes

D.the new material is unlikely to be used in building bridges

The color-changing molecule can

A.make building materials much stronger

B.help building materials get stretched if necessary

C.prevent the earthquake from killing people

D.remind people to leave buildings before they fall

The warning system is based on the fact that

A.red color won’t show up when it meets bright fight

B.a material with a certain type of molecule Can turn red when stretched etched

C.a building has its own life circle of “birth” to “death”

D.the broken bond will fix itself when a molecule meets bright fight

The light from the campfire brightened the darkness, but it could not prevent the damp cold of Dennis’s Swamp (沼泽地) creeping into their bones. It was a strange place. Martin and Tom wished that they had not accepted Jack’s dare. They liked camping, but not near this swamp.
“So,” Martin asked as they sat watching the hot coals. “How did this place get its name?”
“Are you sure you want to hear it ? It’s a scary story,” warned Jack.
“Of course!” cried out Tom. “If there were anything to be scared of, you wouldn’t have chosen this place!”
“Ok, but don’t say I didn’t warn you,” said Jack, and he began this tale.
“Way back in time, a man called Dennis tried to start a farm here. He built that cottage over there to live in. In those days, the area looked quite different ---- it was covered with tall trees and the swamp was a crystal-clear river. After three hard years, Dennis had cleared several fields and planted crops. He was so proud of his success that he refused to listen to advice.
“‘You are clearing too much land,’ warned one old man. ‘ The land is a living thing. It will hit back at you if you abuse it. ’
“‘Silly fool,’ said Dennis to himself. ‘If I clear more land, I can grow more crops. I’ll become wealthier. He’s just jealous!’”
“Dennis continued to chop down trees. Small animals that relied on them for food and shelter were destroyed. He was so eager to expand his farm that he did not notice the river flowing slowly towards his door. He did not notice salt seeping to the surface of the land. He did not notice swamp plants choking all the native plants.”
“What happened?” Martin asked. It was growing colder. He trembled, twisting his body closer to the fire.
“The land hit back ---- just as the old man warned,” Jack shrugged. “Dennis disappeared. Old folks around here believe that swamp plants moved up from the river and dragged him underwater. His body was never found.”
“What a stupid story,” laughed Tom. “Plants can’t …” Before he had finished speaking, he screamed and fainted (晕倒). The other two boys jumped up with fright, staring at Tom. Suddenly, they burst out laughing. Some green swamp ivy (常春藤) had covered Tom’s face. It was a while before Tom could appreciate the joke.
【小题1】The underlined word “dare” in Paragraph 1 is closed in meaning to ________.

A.courageB.assistanceC.instructionD.challenge
【小题2】Why did Jack tell Tom and Martin the story?
A.To frighten them.
B.To satisfy their curiosity.
C.To warn them of the danger of the place.
D.To persuade them to camp in the swamp.
【小题3】Why did Dennis ignore the warning of the old man?
A.The old man envied him.B.The old man was foolish
C.He was too busy to listen to others.D.He was greedy for more crops.
【小题4】Why did Tom scream and faint?
A.He saw Dennis’s shadowB.He was scared by a plant
C.His friends played a joke on him.D.The weather became extremely cold.
【小题5】What lesson can we learn from the story of Dennis?
A.Grasp all, lose all
B.No sweat, no sweet.
C.It is no use crying over spilt milk
D.He who makes no mistakes makes nothing.

  Things similar continuously happened in Haiti and Chile.Thousands of people were

buried in the earthquake and lost their fives.What if we could have warned them? People are always trying hard to find a way of preventing building collapsing(坍塌).Better materials and technology help,but are not a solution.Just like humans,a building has its own life circle from  “birth” to “death”.If we know when a building is going to collapse,we can repair it in advance or get out before it falls.

    Now, scientists at the University of Illinois have developed a material that turns red before it breaks.The invention could be used in things like climbing ropes,or bridge supports.The secret behind the color-changing material is a type of molecule(分子).A molecule is a group of atoms held together by chemical bonds(化学键).Imagine you and your friends standing in a circle,holding hands.Each person stands for one atom,your hands represent the bonds,and the entire circle represents a molecule.If one person lets go of his or her hands,the molecule changes color.The research team put the molecule into a soft material.When the researchers stretched(拉长) the material:it turned bright red a few seconds before it broke into two pieces.

When they repeatedly stretched and relaxed the material,without breaking it,it only turned a little red.

The major problem is,light can get rid of the red color.When the team shone a bright light on the molecule,the broken bond was fixed,and the color disappeared.If bright fight keeps the red color from appearing,the material’s warning system will be useless.Scientists still have a lot of work to do before the color-changing molecule can be used outside the lab.

1. The passage mainly about

A. a way of preventing building from breaking down

B. a series of earthquakes in Haiti and Chile

C. a way of warning before buildings collapse

D. a newly-discovered structure of a molecule

2.According to the passage,we can conclude that

A.there are problems to solve before putting the new material to use

B.scientists have found the life circle of buildings from “birth” to “death”

C.bright fight makes the red color visible to human eyes[来源:Z&xx&k.Com]

D.the new material is unlikely to be used in building bridges

3.The color-changing molecule can

A.make building materials much stronger[来源:Zxxk.Com]

B.help building materials get stretched if necessary

C.prevent the earthquake from killing people

D.remind people to leave buildings before they fall

4.The warning system is based on the fact that

A.red color won’t show up when it meets bright fight

B.a material with a certain type of molecule Can turn red when stretched etched

C.a building has its own life circle of “birth” to “death”

D.the broken bond will fix itself when a molecule meets bright fight

 

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