Both of us are interested in babysitting for Mrs.Martin.
Explanation - Either of us would indicate that either one or the other is interested, and can be confusing. Both shows that multiple people are interested in babysitting.
You can't go around building a better world for people. Only people can build a better world for people. Otherwise it's just a cage. Besides you don't build a better world by choppin' heads off and giving decent girls away to frogs.”