[{'role': 'USR', 'utterance': 'I have found it quite different here from China since I came to the United States.'}
 {'role': 'SYS', 'utterance': "What's the difference?"}
 {'role': 'USR', 'utterance': 'Some friends of mine took me to the mall to go shopping. It was so big. I think I could get lost if I went there alone.'}
 {'role': 'SYS', 'utterance': 'You must have bought many things in the mall?'}
 {'role': 'USR', 'utterance': 'Not really many. I was told that on weekends there were always the flea markets, so I decided to come to the flea market to buy a bargain.'}]
{'role': 'SYS', 'utterance': "It's wise to do it. The Americans have the habit of selling their junk when they are moving to another place, so they usually display all the things they want to sell in their gardens at the weekend. And many things they are selling still look quite new and they are also very useful."}