. . . () = Not strummed but continued from the last strike of the note. Letting it ring out this point. Usually used where the timing needs a beat writing so you know if it's the 8th note the 3rd b3at or 4th beat. Something similar to that. Also where a slide doesn't strike the note but just it ring, and also where a note continues over into a new bar. 4. Put the bloody timing in for God's sake. I am so sick of Tab without the timing. 5. For fast note changes, you can slow down the play (guitaretab.com)