public void DropEvt(Circumstance C, Literal l, Unifier un)
{
Trigger te = new Trigger(TEOperator.add, TEType.achieve, l);
//search in E
C.RemoveEvents(te, un);
// search in PE (only the event need to be checked, the related intention is handled by dropInt)
C.RemovePendingEvents(te, un);
}