The World's Water Shortage

　　The world is not only hungry, but it is also thirsty for water.This may seem strange to you, since nearly 70 percent (百分比) of the earth's surface is covered with water. But about 97 percent of this huge amount is sea water, or salt water. Man can only drink and use the other 3 percent－the fresh water from rivers, lakes, underground, and other sources(资源) . And we cannot even use all of that, because some of it is in the form of icebergs and glaciers (冰川). Even worse, some of it has been polluted.

　　However, as things stand today, this small amount of fresh water is still enough for us. But our need for water is increasing (增加) rapidly－almost day by day. Only if we take steps to deal with this problem now can we avoid (避免) a severe (严重的) worldwide water shortage later on.

　　We all have to learn how to stop wasting our valuable water. One of the first steps is to develop ways of reusing it.

　　Today in most large cities, water is used only once and then sent out into a sewer system (下水道). From there it returns to the sea or runs into underground storage tanks. But it is possible to pipe used water to a purifying (净化) plant. There it can be treated with chemicals so that it can be used again, just as if it were fresh from a spring.

　　But even if every large city purified and reused its water, we still would not have enough. All we'd have to do to make use of the vast reserves (贮备) of sea water in the world is to remove the salt.

　　If we take these steps we'll be in no danger of drying up.

1．The world is thirsty for water because we can only use ________ percent of the water covering the surface of the earth.

[　　]

2．Which of the following statements is Not true?

[　　]

A．As things remain unchanging, this small amount of fresh water is still enough for us.

B．Our need for water is becoming larger and larger.

C．There will be no water shortage in the future.

D．We should take steps to deal with the water shortage problem.

3．To reuse water, we should ________ .

[　　]

A．treat it with chemicals

B．use it only once

C．send it out into a sewer system

D．make it flow into underground tanks

4．In order to have enough water, we should also make use of ________ .

[　　]

5．In the passage, the writer tells us ________ .

[　　]

A．to make enough water

B．to pay more attention to the water shortage problem

C．to pipe used water to a purifying plant

D．to reuse the water

The World's Water Shortage

　　The world is not only hungry, but it is also thirsty for water. This may seem strange to you, since nearly 70 percent（百分比）of the earth's surface is covered with water. But about 97 percent of this huge amount is sea water, or salt water. Man can only drink and use the other 3 percent--the fresh water from rivers, lakes, underground, and other sources（资源）. And we cannot even use all of that, because some of it is in the form of icebergs and glaciers（冰川）. Even worse, some of it has been polluted.

　　However, as things stand today, this small amount of fresh water is still enough for us. But our need for water is increasing（增加）rapidly--almost day by day. Only if we take steps to deal with this problem now can we avoid（避免）a severe（严重）worldwide water shortage later on.

　　We all have to learn how to stop wasting our valuable water. One of the first steps is to develop ways of reusing it.

　　Today in most large cities, water is used only once and then sent out into a sewer system（下水道）. From there it returns to the sea or runs into underground storage tanks. But it is possible to pipe used water to a purifying（净化）plant. There it can be treated with chemicals so that it can be used again, just as if it were fresh from a spring.

　　But even if every large city purified and reused its water, we still would not have enough. All we'd have to do to make use of the vast reserves（贮备）of sea water in the world is to remove the salt.

　　If we take these steps we'll be in no danger of drying up.

(1) The world is thirsty for water because we can only use ________ percent of the water covering the surface of the earth.

[　　]

A．3	B．more than 3
C．less than 3	D．97

(2) Which of the following statements is not true?

[　　]

A．As things remain unchanging, this small amount of fresh water is still enough for us.

B．Our need for water is becoming larger and larger.

C．There will be no water shortage in the future.

D．We should take steps to deal with the water shortage problem.

(3) To reuse water, we should ________.

[　　]

A．treat it with chemicals

B．use it only once

C．send it out into a sewer system

D．make it flow into underground tanks

(4) In order to have enough water, we should also make use of _________.

[　　]

A．icebergs and glaciers	B．sea water
C．rivers and lakes	D．underground water

(5) In the passage, the writer tells us ________.

[　　]

A．to make enough water

B．to pay more attention to the water shortage problem

C．to pipe used water to a purifying plant

D．to reuse the water

阅读理解

　　Hundreds of years ago, travelers found their way by looking at the stars. They built towers that could be seen from far, made maps and invented the compass. Nowadays, almost every explorer and mountain climber uses the Global Positioning System (GPS,全球定位系统) to make their journeys safer. There are even plans to put GPS receivers on all the taxis in Beijing in time for the 2008 Olympics. Finding your way has never been so easy.

　　Technology has changed our lives：for less than 500 yuan, you can get a pocket-sized GPS gadget (小配件) that will tell you exactly where you are on Earth at any moment.

　　When people talk about a GPS, they usually mean a GPS receiver. The GPS is actually a set of 27 Earth-orbiting satellites—24 in operation and three extras in case one fails.

　　The US army developed this satellite network as a military navigation (导航) system in the 1970s, but opened it up to business use in the 1990s.

　　Each of the solar-powered satellites circles the globe twice every day. The orbits are arranged so that at any time, anywhere on Earth, there are at least four satellites “visible” in the sky.

　　A GPS receiver locates these satellites, records the distance to each, and uses the information to calculate the receiver's exact position on Earth.

　　A standard GPS receiver doesn't only identify (识别) your position on a map, but can also trace your path across the map as you move. If you leave your receiver switched on, it can stay in touch with the satellites to see how your location is changing.

　　Although it is based on a very simple idea, the contribution GPS has made to plane and sea travel, military operations and adventure sports means. It is one of the most revolutionary (革命性的) inventions of all time.

根据文章内容回答下列问题

1．How did travelers find their way hundreds of years ago? How many ways do you know from the passage?

2．Who first developed GPS satellite network?

3．How much do you need to pay for a pocket-sized GPS gadget?

4．What do people mean when they talk about a GPS?

5．What can a standard GPS receiver do?