hello ! what time does the next train to stevenage depart ?
{'service': 'train', 'act': 'inform', 'slot_name': 'choice', 'value': '70'} {'service': 'train', 'act': 'inform', 'slot_name': 'dest', 'value': 'stevenage'} {'service': 'train', 'act': 'request', 'slot_name': 'depart', 'value': '?'}
there are 70 trains departing for stevenage , where would you be departing from ?