i need a train leaving from cambridge and should leave on tuesday .
{'service': 'train', 'act': 'inform', 'slot_name': 'choice', 'value': 'several'} {'service': 'train', 'act': 'request', 'slot_name': 'dest', 'value': '?'}
there are several trains that may suit your needs . do you have a particular destination in mind ?