Years passed by, but questions are around. If you don´t know, probably your are acquitted with other programs, then Adobe. If you have a problem using the now CS 5.5 may be you are searching the wrong command. As you wish to “split” a clip or make a “cut”, you will not find’em at keyboard shortcuts. “Cut” for Adobe is cut&paste. Split are vertical splitting os tracks. What you need is ADD EDIT a very proprietary language. So, search for ADD and you will find immediately ADD EDIT and ADD EDIT ALL TRACKS. Simply choose your preferred key, because ctrl-something if a terrible choice. As an old Avid Liquid professional I ever cut clips with “.” and all track with “;” – have a good edit.