用适当的话语补全下面对话
A: Are you busy this afternoon,Bill?
B: (1)____________________.
A: Let's go to the zoo then.
B: Good idea. (2)_____________________?
A: Dolphins are my favorite. They are very clever. They often help us in the water.
B: (3)____________________?
A: I like pandas.
B: Me too. They are really very cute. But do you know where they are from?
A: (4)____________________. I think.
B: Yes, (5)____________________. Oh , it's time for class. Let's go into the classroom.
A: OK. Let's.
(1)_____________________
(2)_____________________
(3)_____________________
(4)_____________________
(5)_____________________