题目内容：

听下面一段独白，回答以下小题。

1.What did Marco Polo see when he was in China?

A. The Chinese invented paper.

B. The Chinese used paper money.

C. The Chinese planted trees for paper.

2.When did people in western countries first use paper money?

A. In the 7th century.    B. In the 13th century.    C. In the 15th century.

3.How many trees should be cut down to make one ton of paper?

A. 17.    B. 48.    C. 71.