i am looking for a train that leaves on tuesday to cambridge , please .
{'service': 'train', 'act': 'request', 'slot_name': 'arrive', 'value': '?'} {'service': 'train', 'act': 'request', 'slot_name': 'leave', 'value': '?'}
kindly narrow down your specification -s so that i can find you a train that suits you best , like time of arrive and departure