问题 问答题

如图所示,用细线将一小球静止的悬挂在空中,用一个未敲击的音叉慢慢的接触小球,小球未发生任何现象.当用敲击后且发声的音叉慢慢的接触小球,发现小球被弹动,这一现象说明声音是由于物体的______而产生的.

答案

一切发声的物体都在振动,发声的音叉也在振动,所以会将接触它的塑料球弹开;

故答案:振动

阅读理解

阅读理解。

     Many animals do strange  things  before    an earthquake(地  震).  This news may  be  important.

Earthquakes can kill people and knock down  homes. The animals may help to save lives.

     Some animals make a lot of noise before an earthquake. Farmers have told about this. Dogs  that

are usually quiet have started to howl(吠). Horses on farms have run around in circles. Mice have left

their holes and run away. Cows have given less milk.

     In a town in Italy, cats raced down the street in a group. That happened only a few hours  before

an earthquake. In San Francisco, a man kept tiny pet frogs. One Sunday, the frogs jumped   around

more than ever. They made loud noises, like bigger frogs. That night, an earthquake struck   the  city.

   People want to know when an earthquake is coming. Then they could get away safely. Right now,

there is no sure way to know ahead of time. Maybe the best way is to watch the animals.

1.This story is mostly about _________. 

A.how animals act before an earthquake

B.how an earthquake starts

C.how mice leaves their homes

D.when an earthquake begins

2.Before an earthquake, quiet dogs _________.

A. ran away

B. started to howl

C. climbed trees

D. race down streets

3. Before an earthquake, the frogs _________. 

A. sang

B. left their homes

C. jumped around a lot

D. become quiet

4.There have been earthquakes in _________.

A. most countries    

B. Italy and San Francisco

C. Chicago and Spain  

D. all the western countries

5.People want to _________.

A. be in earthquake        

B. find out early about an earthquake

C. run around in circles    

D. get away from earthquakes

单项选择题 B1型题