System
 
 
 
We have a good heating system.
There is an urgent need for a new system.
Our dorm's heating system isn't working properly.
There is an urgent need for them to update their system.
I think it wouldn't be too hard to come up with a better system.
The ancient Greeks knew as much about the solar system as we do.
I'm sure it wouldn't be too hard to find out who hacked into our system.