Sentence:The [e1]sand[/e1] in the [e2]hourglass[/e2] solves several problems of the clepsydra: it does not freeze in cold temperatures, it does not evaporate in warm weather, and it can be sealed so nothing can get in that will affect the flow of the sand in the glass.
 e1: sand. 
 e2 : hourglass.
Answer: Content-Container(e1,e2)