Tā duì nàge xiàngmù bùwénbùwèn, rèn qí zìshēngzìmiè.
He ignored the project and let it run its course.
Tips
usage
Often implies neglect or indifference — letting something live or die without intervention. Frequently paired with 任其 (rèn qí, let it) or 听其 (tīng qí, leave it to).