题目内容：

听下面一段独白，回答以下小题。

1.Why did the post office in Guyana print their own special stamps?

A.They wanted to make more money.

B.They had only a few usual stamps left.

C.There were no 1-cent or 4-cent stamps then.

2.How much was the l-cent stamp sold for in 1980?

A.A few dollars. B.Seven thousand dollars. C.Seven million dollars.

3.Why are stamps with mistakes so valuable?

A.They are very limited. B.They are very beautiful. C.They were made long ago.

4.What is the text mainly about?

A.The history of the stamps.

B.Things learned from stamps.

C.Reasons for collecting stamps.