What can I do in C# 5 with .Net 4.5 that I couldn't do in C# 4 with .Net 4? [closed]

Question

I have Visual Studio 2012 RC installed on Windows 8 Release Preview and my question is are there any useful new features not related to Metro, or is Metro what seperates .Net 4 and .Net 4.5?

Answer 1

See What's New in the .NET Framework 4.5 and What's New for Visual C# in Visual Studio 2012.

The biggest new feature of C# 5.0 is better support for asynchronous operations, using the new await keyword.