i want to book a train . list all tuesday departures to cambridge .
{'service': 'train', 'act': 'inform', 'slot_name': 'choice', 'value': 'over 200'} {'service': 'train', 'act': 'inform', 'slot_name': 'day', 'value': 'tuesday'} {'service': 'train', 'act': 'inform', 'slot_name': 'dest', 'value': 'cambridge'} {'service': 'train', 'act': 'request', 'slot_name': 'depart', 'value': '?'} {'service': 'train', 'act': 'request', 'slot_name': 'leave', 'value': '?'}
there are over 200 departures to cambridge on tuesday , do you have a specific departure place or time ?