x1 precedes/leads x2 in sequence x3; x1 is former/preceding/previous; x2 is latter/following.
Also x1 before, forerunner; leading, as in 'leading indicators'; x2 after, trailing (= selyli'e for reordered places). See also cmavo list li'e, balvi, ralju, rebla, purci for time sequence, jersi, porsi, jatna, farna.