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”?

What __________ things do you want to buy?

A. else                  B. other            C. others               D. another

What to Bring When Visiting Lijiang of Yunnan
Welcome to Lijiang. Lijiang is a nice place to visit. If you visit Lijiang, you’d better do as the following.

Food or friends? Lip salve (润唇膏) or iPod? What is the most important thing in the US teenagers’ lives today? Let’s take a look.

Some find that they can’t do without people.

“My biggest need is my friends. Without them, I wouldn’t do much,” said Adrian Fernandez, a 14-year-old boy.

With others, food always comes first.

“I do not think that I could live without chili con carne (辣子肉丁). I eat it every day. And if I didn’t have it, it’s all I would think about,” said Max Wu, an 8th-grade boy.

Sometimes, the things teenagers can’t do without are strange.

Take 14-year-old girl Hannah Sacchini for example. “I cannot live without lip salve, especially in winter,” said Hannah Sacchini. “I go mad if my lips get dry.”

Of course, today everybody uses mobile phones and computers. Some teens can’t live without these high-tech (高科技的) things.

Justin Beck, a 15-year-old boy, feels like this: “I would not be able to live without my iPod. I use it for so many different things. I always have it with me,” he said.

So, now we know the things US kids really must have. What about you and your classmates? What can’t you live without?

根据短文内容，选择最佳选项。 （10分）

1.To Adrian Fernandez, 　　　 is the most important.

A．a friend           B．lip salve           C．a computer        D．chili con carne

2.How often does Max Wu eat chili con carne?

A．Once a week.                          B．Every day.

C．Twice a day.                            D．Three times a week.

3.Hannah Sacchini will become 　　　 if her lips get dry.

A．fat               B．excited           C．shy              D．annoyed

4.We can learn that Justin Beck 　　　 takes his iPod to school.

A．never            B．sometimes         C．always            D．hardly ever

5.The passage mainly tells us 　　　.

A．what things the US kids really must have

B．what the US teenagers do every day at school

C．what the most important food in the US teenagers’ lives is

D．how the US teenagers’ lives are every day at school