In SQL Server Management Studio 2008, I tends to write a lot of queries in a single window and execute a single line of them whenever I need. Hence a shortcut to highlight a sentence is kind of helping a lot.
I've tried all combination of the following but no luck.
Ctrl+Alt+Down
Ctrl+Shift+Down
Alt+Shift+Down
Home Shift+End would do it. I doubt there is a need for anything shorter