Whenpiecemeasures39-42(46-48-50)cmcastoffthemiddle34-34(36-38-38)stsforneckanddec1stonnecklineonnextrow.

Please segment the words:
When piece measures 39-42 (46-48-50) cm cast off the middle 34-34 (36-38-38) sts for neck and dec 1 st on neckline on next row.