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You and your friends are talking about ghost（鬼）stories. Suddenly, a surprising sound comes from upstairs. And your bookshelf begins to creak（嘎吱响）...
Feeling scared? It's time to learn some science! Then you will find that all the "ghosts" are just simple physics!
Squeak, creak
At night, we often hear furniture make some creaking sounds. That's because things expand when heated and contract when cooled（热胀冷缩）. During the day, the temperature is high. At night, the air cools down. The change in temperature makes the furniture expand and contract and make sounds. The same science goes for the strange sounds from your TV after you turn it off.
Bouncing marbles
Have you ever heard the noise of "marbles（弹子）" from upstairs? That's not really children playing marbles. Scientists say the sound may come from pipes（管道）in the building. When water goes through a pipe, it pushes the air inside. That could make the sound of a dropping marble.
Mold（霉菌）might also be the "ghost" behind the wall. It grows in the cracks（缝隙）and eats the cement（水泥）. Then the rebar（钢筋）will stretch a little. That makes the sound of dropping marbles, too.
Humming sound
There are some low-frequency（低频的）sounds people can't hear. But studies showed that some people can feel this kind of sound. They will feel scared and nervous. Living near such sounds could make you feel like someone is watching you.
1. Why does the furniture make strange sounds at night?
A. Because there are some monsters in it.
B. Because ghosts come out to break it at night.
C. Because its temperature changes from day to night.
D. Because the TV on it makes the strange sounds.
2. According to the passage, what can cause the sound of dropping marbles?
a. children sleeping upstairs
b. water going through a pipe
c. mold growing in the wall
d. cement dropping on the ground
A. ab
B. bc
C. ac
D. bd
3. What does the underlined word "It" refer to?
A. Noise.
B. Mold.
C. The pipe.
D. The rebar.
4. How might some people feel if they live near low-frequency sounds?
A. It's hard to hear other sounds around them.
B. They are living in a low place.
C. It's too noisy for them to stay there.
D. There is someone watching them.
5. What is the passage mainly about?
A. How to know the temperature.
B. Where to find ghosts in a house.
C. Interesting physics for children.
D. Science behind some strange sounds.
You and your friends are talking about ghost（鬼）stories. Suddenly, a surprising sound comes from upstairs. And your bookshelf begins to creak（嘎吱响）...
Feeling scared? It's time to learn some science! Then you will find that all the "ghosts" are just simple physics!
Squeak, creak
At night, we often hear furniture make some creaking sounds. That's because things expand when heated and contract when cooled（热胀冷缩）. During the day, the temperature is high. At night, the air cools down. The change in temperature makes the furniture expand and contract and make sounds. The same science goes for the strange sounds from your TV after you turn it off.
Bouncing marbles
Have you ever heard the noise of "marbles（弹子）" from upstairs? That's not really children playing marbles. Scientists say the sound may come from pipes（管道）in the building. When water goes through a pipe, it pushes the air inside. That could make the sound of a dropping marble.
Mold（霉菌）might also be the "ghost" behind the wall. It grows in the cracks（缝隙）and eats the cement（水泥）. Then the rebar（钢筋）will stretch a little. That makes the sound of dropping marbles, too.
Humming sound
There are some low-frequency（低频的）sounds people can't hear. But studies showed that some people can feel this kind of sound. They will feel scared and nervous. Living near such sounds could make you feel like someone is watching you.
1. Why does the furniture make strange sounds at night?
A. Because there are some monsters in it.
B. Because ghosts come out to break it at night.
C. Because its temperature changes from day to night.
D. Because the TV on it makes the strange sounds.
2. According to the passage, what can cause the sound of dropping marbles?
a. children sleeping upstairs
b. water going through a pipe
c. mold growing in the wall
d. cement dropping on the ground
A. ab
B. bc
C. ac
D. bd
3. What does the underlined word "It" refer to?
A. Noise.
B. Mold.
C. The pipe.
D. The rebar.
4. How might some people feel if they live near low-frequency sounds?
A. It's hard to hear other sounds around them.
B. They are living in a low place.
C. It's too noisy for them to stay there.
D. There is someone watching them.
5. What is the passage mainly about?
A. How to know the temperature.
B. Where to find ghosts in a house.
C. Interesting physics for children.
D. Science behind some strange sounds.
答案
1-5 CBBDD
