We our using Solid Works in our high school engineering course, and our first task was to recreate a 1x8 LEGO beam.  After making the beam I read the next instructional document and it said that if any of my sketches had "(-)" before the sketch that my instructor would not evaluate my piece.  All of my sketches had the "(-)".  He said it means that only part of my sketch is being affected, but i don't understand what he is trying to say.   If anyone can help me with this I would greatly appreciate it.