l+vt =ct l-vt,ct2 i1-t2= 1-12E点A c-v c+v G2-v 21- The simultaneous events in S'may not happen at the same time in S 2 2 2 2 2 1 2 1 ' 2 ' 1              x c v c v l v c v l c v l t t The simultaneous events in S’ may not happen at the same time in S