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: 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, dB.c, a, b, dC.d, c, b, aD.d, b, c, a
小题2:. 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
小题3: If you haven’t got a megaphone, ____ will help you to make your voice travel farther.
A.a long piece of woodB.a roll of cardboard
C.a thin threadD.a long piece of silk

Earthquakes can be very scary(吓人的). But you need to keep your mind stable (坚定的) in order to make sure you are safe. Be calm and try not to run here and there.
If you manage to come out of your house, go to an open space like a garden or a park where you will be a lot safer. If you live quite some floors above in your building, try to find a place near a bulky(坚固的) object such as a bed. Curl up (蜷缩) and sit on the floor and make sure you are not near a window, fireplace, gas stove and so on. Remember don’t use lifts or escalators.
Some people say you should stand on a doorway. That is not true. If the doorway jambs (侧壁) are weak, they might fall on you. Also if people want to pass through that door, you may stop them. Leave all doorways free.
Another important thing to keep in mind is that you mustn’t climb down the stairs during an Earthquake. If the tremors (震动) stop, after a few seconds, just climb down the stairs as quickly as you can and move out of the building, but don’t run.
Earthquakes usually destroy gas pipes and electrical wires. Turn off the main gas. And don’t light candles or lighters and create an even bigger disaster.
If you’re driving and feel a shake, stop your car at the side of the road and get out. Make sure you are not on a bridge. Bridges and overhead roads (高架路) have the biggest danger of falling.
小题1: The best title for the passage should be       .
A.Dos and Don’ts Before an Earthquake.
B.What to Do in Case of Earthquake
C.Tips for Earthquake Preventions
D.Tips for Children in Earthquake.
小题2:When an earthquake suddenly happens, you should       .
a. remain standing near a window             b. turn off the main gas
c. stay in an open space                     d. stand on a doorway
e. keep off  overhead roads
A.a, b, cB.c, d, eC.b, c, eD.b, d, e
小题3: Which of the following is NOT true, when an earthquake suddenly happens?
A.We can’t use the lift.
B.Curling up may be very dangerous.
C.We must turn off the gas.
D.We must get out of the car when the earthquake comes
小题4: It can be learned from the passage that     .
A.keeping calm in time of earthquake is very important.
B.measures should be taken to make buildings stronger.
C.Knowledge of first aid must be used in an earthquake.
D.lots of things must be done to survive an earthquake.
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