Store the same entity but at different points in time

Hi,
I want to store the same data but at different points in time. How can I do it?

For example:

Time: 3/23 10:00

A 10
B 20
C 30

and then next time:

Time: 3/23 10:10

A 15
B 25
C 35

I want to keep the two data simultaneously and then I can calculate the difference between them.

Thanks very much

You can represent a set of measurements at a specific time as its own entity and each measurement as an edge off of it:

:Measurement20200323T1000 a :Measurement ;
  :takenAt "2020-03-23T10:00:00Z"^^xsd:dateTime ;
  :aValue 10 ;
  :bValue 20 ;
  :cValue 30 .

:Measurement20200323T1010 a :Measurement ;
  :takenAt "2020-03-23T10:10:00Z"^^xsd:dateTime ;
  :aValue 15 ;
  :bValue 25 ;
  :cValue 35 .

Hi stephen,
Okay, I got it.
Thank you.