Have you ever heard an echo of your voice?

An echo is a reflected(反射)sound. Stand in a very large, empty hall with nothing on the walls. Then shout. The sounds you make will hit the walls and come back to you. The walls reflect the sounds. These reflected sounds are called “echoes”.

We can use reflected sound to make sound travel farther. Hold a watch about fifty centimeters from your ear. You cannot hear it. The sound of the watch travels a short way in all directions. It does not travel as far as your ear. You can make it travel to your ear by using a roll of cardboard(纸板筒).

Make the roll of cardboard about fifty centimeters long. Put one end over your ear and hold the watch at the other. Now you can hear the watch because the sound has not gone in all directions. It is reflected down the roll to your ear.

A megaphone(喇叭筒)works in the same way. It makes sound travel farther. It reflects the sound into a beam which can travel a long way. In the ship, the sailor uses the megaphone to make his voice travel. Without the megaphone, his voice cannot travel far.

We use reflected sound in many ways. We use it to measure the depth of the sea, for example. Among the animals, bats and whales use reflected sound to tell them where they are and what things are near them.

1.What is called “echo”?

A．Very loud voices.

B．Very loud voices that are made by man.

C．Very loud voices that are made by animals.

D．The sound that is made by man or animals comes back from some place.

2.We can hear our echoes if we     .

A．shout in a small room

B．shout in a large house full of things

C．shout in narrow valleys(山谷)

D．shout in the open air

3.Which is the right order of hearing our echo in a very large, empty hall?

a. We hear the reflected sound

b. The sound returns to us

c. The sound hits the walls

d. We make a sound

A．c, b, a, d          B．c, a, b, d           C．d, c, b, a           D．d, b, c, a

4.From the text we learn that __________ .

A．reflected sound is useful only to blind people

B．people haven’t made use of reflected sound yet

C．bats use reflected sound to fly and get food

D．whales don’t use reflected sound as they live in the sea

5.If you haven’t got a megaphone, ____ will help you to make your voice travel farther.

A．a long piece of wood                     B．a roll of cardboard

C．a thin thread                           D．a long piece of silk

Have you ever heard an echo of your voice?

An echo is a reflected(反射)sound. Stand in a very large, empty hall with nothing on the walls. Then shout. The sounds you make will hit the walls and come back to you. The walls reflect the sounds. These reflected sounds are called “echoes”.

We can use reflected sound to make sound travel farther. Hold a watch about fifty centimeters from your ear. You cannot hear it. The sound of the watch travels a short way in all directions. It does not travel as far as your ear. You can make it travel to your ear by using a roll of cardboard(纸板筒).

Make the roll of cardboard about fifty centimeters long. Put one end over your ear and hold the watch at the other. Now you can hear the watch because the sound has not gone in all directions. It is reflected down the roll to your ear.

A megaphone(喇叭筒)works in the same way. It makes sound travel farther. It reflects the sound into a beam which can travel a long way. In the ship, the sailor uses the megaphone to make his voice travel. Without the megaphone, his voice cannot travel far.

We use reflected sound in many ways. We use it to measure the depth of the sea, for example. Among the animals, bats and whales use reflected sound to tell them where they are and what things are near them.

1. Which is the right order of hearing our echo in a very large, empty hall?

a. We hear the reflected sound       b. The sound returns to us  

c. The sound hits the walls          d. We make a sound

2.. From the text we learn that __________ .

3. If you haven’t got a megaphone, ____ will help you to make your voice travel farther.

根据短文内容及首字母提示，填写所缺单词，使短文意思完整。每空限填一词。

Bill and Simon were good friends. One summer they were on h         . They wanted to sail around the Caribbean Sea in their boat for two weeks.

During their trip, they saw many whales. Bill and Simon were very e         because they had wanted to see them very much. Unluckily, w         they were watching them, the whales began to hit the side of the boat.

Suddenly, w         started coming in, and they realized that they were in trouble. They q         jumped into the lifeboat before the sank(沉没), and watched it disappear under the sea.

Luckily, they had enough food and water for about twenty d         . They also had a fishing line and a machine which could change sea water i         drinking water. These two things helped them to survive(存活) during their terrible experience.

For the next fifty days they caught about ten fish a day and a         them. They saw about twenty ships, but although they waved and shouted when the ships were passing, n         saw them. They were becoming weaker and weaker. Then, just as they were beginning to l         hope, a fishing boat saved them.

Bill and Simon were good friends. One summer they were on (1) h   ____    . They wanted to sail around the Caribbean Sea in their boat for two weeks.
During their trip, they saw many whales. Bill and Simon were very (2) e__________ because they had wanted to see them very much. Unluckily, (3) w   __   ___  they were watching them, the whales began to hit the side of the boat.
Suddenly, (4) w ______       started coming in, and they realized that they were in trouble. They (5) q_ _____       jumped into the lifeboat before the sank(沉没), and watched it disappear under the sea.
Luckily, they had enough food and water for about twenty (6) d     __ ___. They also had a fishing line and a machine which could change sea water () i             
drinking water. These two things helped them to survive(存活) during their terrible experience.
For the next fifty days they caught about ten fish a day and (8) a  _____      them. They saw about twenty ships, but although they waved and shouted when the ships were passing, (9) n _________       saw them. They were becoming weaker and weaker. Then, just as they were beginning to (10) l _______________  hope, a fishing boat saved them.  

Have you ever heard an echo of your voice?
An echo is a reflected(反射)sound. Stand in a very large, empty hall with nothing on the walls. Then shout. The sounds you make will hit the walls and come back to you. The walls reflect the sounds. These reflected sounds are called “echoes”.
We can use reflected sound to make sound travel farther. Hold a watch about fifty centimeters from your ear. You cannot hear it. The sound of the watch travels a short way in all directions. It does not travel as far as your ear. You can make it travel to your ear by using a roll of cardboard(纸板筒).
Make the roll of cardboard about fifty centimeters long. Put one end over your ear and hold the watch at the other. Now you can hear the watch because the sound has not gone in all directions. It is reflected down the roll to your ear.
A megaphone(喇叭筒)works in the same way. It makes sound travel farther. It reflects the sound into a beam which can travel a long way. In the ship, the sailor uses the megaphone to make his voice travel. Without the megaphone, his voice cannot travel far.
We use reflected sound in many ways. We use it to measure the depth of the sea, for example. Among the animals, bats and whales use reflected sound to tell them where they are and what things are near them.
【小题1】What is called “echo”?