题目内容：

    In the 13th century（世纪）, the famous Italian traveler, Marco Polo, traveled a long way to China. During his stay in China, he saw many wonderful things. One of the things was paper money. People in the West didn’t use the paper money until the 15th century. However, the Chinese began to use it in the 7th century.

Paper was invented（发明）by a Chinese man called Cai Lun almost 2, 000 years ago. But it was not made in the West until the year 1100. Four hundred years later, a German found that he could make the best paper from trees. After that countries with plenty of forest, such as Canada, Sweden, America and Finland, became the most important ones in paper making.

Paper can be used in many ways. It can be used in newspapers, magazines and books. But do you know that paper can be used for keeping warm? In Finland, the farmers wear paper boots to keep their feet warm in the snow. And even houses can be insulated（使绝缘）from heat or cold with paper.

However, we have to understand that paper still comes from trees now. If we keep on wasting so much paper, there will not be any trees left on the earth some day in the near future. Every day people throw away about 2,800 tons of paper in our city. It takes 17 trees to make one ton of paper. This means that we are cutting down nearly 48,000 trees every day. The fact is that it takes more than 10 years for a tree to grow.

So we must start saving paper right now. We can use both sides of every piece of paper. We can make useful things out of used paper. We can use china cups instead of paper ones. When shopping, we can use fewer paper bags and reuse them if we have some.

In short, we should keep a balance（平衡）between using paper and protecting trees, and do it now before it is too late.

1.When did the Chinese begin to use paper money?

A. In the 5th century. B. In the 6th century.

C. In the 7th century D. In the 15th century.

2.Why did Canada become an important country in paper making?

A. Because it was a large country. B. Because it had lots of forests.

C. Because it was a very rich country. D. Because the inventor was from Canada.

3.What is the writer’s main purpose in writing this passage?

A. To explain how to make paper. B. To introduce where paper is from.

C. To show Marco Polo’s great travel. D. To encourage people to save paper.