[{'role': 'USR', 'utterance': 'Excuse me, could you tell me which bus I should take to go to the railway station?'}
 {'role': 'SYS', 'utterance': "I think you'd better take the No. 16 bus. It can take you right there."}
 {'role': 'USR', 'utterance': 'How often dose this bus go there?'}
 {'role': 'SYS', 'utterance': 'Every fifteen minutes.'}
 {'role': 'USR', 'utterance': "I really can't wait that long. Are there any other buses that can take me there?"}
 {'role': 'SYS', 'utterance': 'The No. 2 bus also goes to the railway station. You may take it.'}
 {'role': 'USR', 'utterance': 'Where can I find the bus?'}]
{'role': 'SYS', 'utterance': 'The bus stop is not far from here. Go straight on and you can easily find it.'}