Answer:
"I plan to buy a hybrid for better gas mileage, but for now I am able to carpool with a couple of friends from work."
"The architects just received a LEED certification for the design."
Explanation:
The first sentence is about getting a hybrid car. This car will use less gas and have better mileage. Therefore saving gas and leading to a more sustainable living.
The second sentence speaks about a LEED certification. This is about creating sustainable building, building the greenery in neighborhoods, and having cost-effective strategies.