user_turns: <SILENCE> let me get some world food and i dont care about the price range how about vietnamese food <SILENCE> how about vietnamese food <SILENCE> what is the address thank you good bye
system_turns: Hello , welcome to the Cambridge restaurant system . You can ask for restaurants by area , price range or food type . How may I help you ? I am sorry but there is no world restaurant that matches your request api_call world R_location R_price gourmet_burger_kitchen is a great restaurant serving north_american food and it is in the expensive price range api_call vietnamese R_location R_price thanh_binh is a great restaurant serving vietnamese food and it is in the cheap price range Sure , thanh_binh is on thanh_binh_address  you are welcome