In the time it takes you to read this sentence, the population of the Earth will have grown by 10 people. That may not sound much, but it is about 14,000 people an hour. That is the same as adding most of the population of Germany to the world every year!

    Most of these new people are born in developing countries. These countries are found in much of Africa, South America, and parts of Asia. In the developed countries of Europe and North America, the population is growing very slowly. This is because women in these countries have, on average, only one or two children. In the developing countries, many women have five or more children. In 1950, around one quarter of the world's population lived in the developed countries. By 2050, these countries will be the home to only around one tenth of the world's people.

    In the developing countries, more than one billion people already live below the poverty line (贫困线).These people don't have enough food to eat and they live in poor housing; children get little or no time at school and suffer from many kinds of diseases.

    The United Nations (UN) tries to guess population growth. At the beginning of the 21st century, the world's population was around six billion people. The UN has said that the world's population will level off at 12. 5 billion people by the year 2100. Other people think the world's population will continue to grow, reaching 14 billion people before it becomes stable or even falls.

Suggested questions:

1）Why should we save water?

2）What are the bad habits that many people have?

3）What are your suggestions?

    One day at Bluesea Middle School in Hong Kong, about 450 students and teachers went without water at lunchtime. They were in a meeting to learn about saving water. The school also collected about HK $ 10,000. The money would be to plant 1,880 trees at the heads of the Yangtze River and the Yellow River.

    The local director of "Friends of the Earth, Ms Wong, explained that  of the world's population still didn't have enough water for all their . She thought that by the year 2020, one half of the world's population would not have enough water. Ms Wong said she had visited the heads of the two rivers three times in the past year. "I had expected them to be clean places, as they are at the top of the rivers., sadly I found that they were polluted seriously, even worse than a few years ago."

    Ms Wong said that if everyone helped save water, the situation would get a little . She hoped that everyone could do something for saving. One of the students said, "I'm pleased to come to the meeting. Now I can remember how a third of the population lives. I think I'll try andsome of my habits. Let's save water together.'