根据下面的对话情景．在每个空白处填上一个适当的句子、使对话的意义连贯、完整。
A: Hello! May I speak to Bruce?
B: __________________.
A: Hi, Bruce. This is David. I haven't seen you for a long time._______________________?
B: I have been to Shanghai. I came back this morning.
A: Really? __________________?
B: I went there with my parents. We had a wonderful time there.
A: _______________________?
B: We visited the World Expo Park. We also went to the Oriental Pearl Tower and toured the Huangpu River.
A: ____________________?
B: Sure. The World Expo 2010 started on May 1^st, 2010 and it will end on October 31^st, 2001. People can see different countries' pavilions and experience different cultures without going abroad. If you miss this chance, you will regret.
A: I hope I can have a chance to visit the World Expo 2010 Shanghai during the summer vacation.
B: I hope so.