You can use that reference type to indicate ... In addition, you learned how to implement interfaces and why multiple interface inheritance is safe. Finally, you witnessed the power of the interface.

No instantiation: You can use both abstract classes ... it can implement several interfaces. By implementing multiple interfaces, you can simulate multiple inheritance by leveraging interfaces ...

A controversial new proposal for .NET suggests the introduction of a limited form of multiple inheritance ... the interface author can provide an overridable implementation which could alleviate ...