题目内容：

补全对话（10分）

A：Hi, Jack. Do you know what the Four Inventions are ?

B: Yes, I have just learned about them from my Chinese teacher.  1.

A: 2.

B: They were great inventions at that time.  3.They are great gifts to the world from ancient China.

A: Really? Can you describe them in detail?

B: Sure. Let me give you an example. Before the compass was invented, sailors had to depend on the stars to find directions. After it was invented, the oceans were open to travel.  4.

A: You are great. You know much about China.

B:  5.