generate response: What time does the one that leaves at 21:39 arrive in Cambridge? Also, what is the train ID?. Intent: find_train. Slots: train-day=monday, train-departure=london liverpool street, train-destination=cambridge, train-leaveat=21:00
Response: The train ID is TR5906 and it arrives by 23:07 in Cambridge. Would you like me to book that one for you?