In some places in North Africa, great cities once stood. There were gardens and trees and grass. But now these places are like deserts(沙漠). Scientists have begun to study this land to find out what happened. Many of them think the land died when the trees were cut down. Trees help other plants grow. Tree roots hold the earth in place. They stop the soil from being blown away. In forests, leaves on the ground keep rainwater from running off. Trees near farms protect growing plants from strong winds.

Once there were hundreds of farms in the Southwestern United States. Then the farms turned into fields of dry land, because few trees grow in the dry Southwest.

Now we try to save trees. In many forests, when a tree is cut down, a new tree is planted in its place. We do not want the land to die.

   Twenty years ago, I lost my son in a traffic accident (交通事故). My friends decided that I needed to get out once a week and so we started going for coffee. Those friends helped me get through that terrible first year and still go on helping me.

We decided that we would try to help people in trouble when we could. So, we take a collection each week and then decide what to do with it. We have paid for breakfasts, helped an elderly man carry water, bought Christmas gifts for needy families, and sometimes just sent flowers to someone who was feeling blue.

We usually do this in a way that no one knows and that makes it even better.

We also have a yearly tea at my house the first Saturday in December to start the Christmas season. We have been "Secret Santa" to three people and each year we try and do something special for someone.

I am thankful for my friends and we are going on helping others.

   Hundreds of years ago, life was much harder than it is today. People didn't have modern machines. There was no modern medicine, either.

Life today has brought new problems. One of the biggest is pollution. Water pollution has made our rivers and lakes dirty. It kills our fish and pollutes our drinking water. Noise pollution makes us talk louder and become angry more easily. Air pollution is the most serious kind of pollution. It's bad to all living things in the world.

Cars, planes and factories all pollute our air every day. Sometimes the polluted air is so thick that it is like a quilt over a city. This kind of quilt is called smog.

Many countries are making rules to flight pollution. Factories must now clean their water before it is thrown away and they mustn't blow dirty smoke into the air.

We need to do many other things. We can put waste things in the dustbin and do not throw them on the ground, there will be less pollution.

Rules are not enough. Every person must help to fight pollution.

   Annie is a neighbor's daughter. When her birthday month came around I found out she felt blue and lonely.

Her family is quite small and kind of poor so there wouldn't be any birthday visitors. I wanted to send her a card and maybe a small gift to make her happy.

I told some of my friends I would like to have a birthday party for the girl. I asked them for help. Then I bought some small presents, a cake and something else.

When the day came, my friends and I went to her house. When she got home after school, we gave the presents to her and wished her a happy birthday.

It was so easy to do something helpful. My friends helped take the party. They still laugh and talk about it. And Annie tells me she likes the birthday very much and she can still remember it!

The world itself is becoming much smaller by using modern traffic and modern communication. Life today is much easier than it was hundreds of years ago, but it has brought new problems. One of the biggest problems is pollution. To pollute means to make things dirty. Pollution comes in many ways. We see it, smell it, drink it and even eat it.

Man has been polluting the earth. The more people, the more pollution. Air pollution is still the most serious. It's bad for all living things in the world, but it is not the only one kind of pollution. Water pollution kills our fish and pollutes our drinking water. Noise pollution makes us angry more easily.

Many countries are making rules to fight pollution. They stop people from burning coal in houses and factories in the city, and from putting dirty smoke into the air. Pollution by SO₂  is now the most dangerous kind of air pollutions. It is caused by heavy traffic. We are sure that if there are fewer people driving, there will be less air pollution.

   Lucy's mother is a pretty woman. She likes new clothes, and she buys many new clothes. They are ___.

Every Saturday she goes shopping _________her friends. Sometimes she buys clothes, and sometimes she helps her friends _________ clothes. She likes _________very much and she enjoys helping _________ on buying things. She always wears beautiful clothes when she _________. Her friends think she is very rich _________she has so many beautiful clothes. But that's not _________. One day she and her husband are at home. She says to her husband, "Dear, look at the old clothes I have to wear! _________ ugly they are! If someone comes to visit our family, they may think I must be a cook."

"A cook?" her husband says. "Do they think you are a cook? And you always buy so many new clothes! Aren't they nice? I think the visitors must _________ their minds if they are at our home and have dinner."