在横线上填句子 Hello ,Sam .Hello,Bill.Come on and have a look .This looks so interesting!

Hello ,Sam .Hello,Bill.Come on and have a look .This looks so interesting!
【Well,What is it about?】
There are dragons and frogs on it.It's a great invention of ancient China.
【Really?When do you think it was invented?】
I think it was invented in Han Dynasty.
【What is it used for?】
Guess!
【Is it used for holding water?】
Holding water?Oh!No.It's used for testing earthquakes .Read these instructions and you'll know how it works.
Wow ,it's really amazing!Now let's search more information about it on the Interent.
【That's a good idea.】