在下面对话的空白处填入适当的话语（话语可以是词、短语或句子），使对话完整．

A：Hi，John．Are you free this Sunday？

B：Yes．（51） 　　？

A：I'm going to plant flowers in the city park．（52） 　　？

B：Sure，I'd love to．Everyone should play a part in making our city beautiful．

A：That's right．

B：（53） 　　？

A：We're going there by taxi．

B：But I think taking a taxi costs too much，How about taking a bus？

A：（54） 　　．Then let's meet at the bus stop on Sunday   morning．

B：OK．（55） 　　！

A：See you!