Keyboard accelerators are configurable. You can find out which keyboard accelerators are bound to a command in Tools -> Options
on the Environment -> Keyboard
page.
These commands are named Edit.CommentSelection and Edit.UncommentSelection.
(With my settings, these are bound to Ctrl+K, Ctrl+C and Ctrl+K, Ctrl+U. I would guess that these are the defaults, at least in the C++ defaults, but I don't know for sure. The best way to find out is to check your settings.)
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…