题目内容：

听下面一段较长对话，回答以下小题。

1.Why was it unusual to see a plane in the early 1900’s ?

A. Because there were few planes.

B. Because the government didn’t want people to see planes.

C. Because planes were sent to fight.

2.What is the relationship between the two speakers?

A. Teacher and student.    B. Mother and son.    C. Father and daughter.

3.What are the speakers talking about?

A. The changes of life.    B. The history of planes.

C. The invention of electric lights.