May , is this the Hall of Ancient China ?
neutral
user
Yes . Look at these historical relics here , amazing !
happiness
assistant
Why are they all in glass boxes ?
neutral
user
For protection . Some relics will turn to dust if exposed to air .
neutral
assistant
So there isn't air in the glass boxes ?
neutral
user
No , there isn't . There is a vacuum in every box .
neutral
assistant
I wonder how old these things are . Thousands of years ?
neutral
user
Yeah , they all come from a very ancient time .
happiness
assistant
Hey , look at the tripod . I've seen it on TV .
happiness
user
It was made 4,000 years ago . It's priceless !
happiness
assistant