完成对话

根据对话内容，在横线上填入一个适当的单词，使对话完整。

A：(1)________．May I speak to Jane, please?

B：(2)________．Who's that?

A：(3)________ is Jack．Jane, it's Peter's birthday on September 20th．I'm planning a party．Are you free on that day?

B：I'm sorry．I can't(4)________．it．I have to look after my younger brother because my parents won't be at home then．

A：Oh, what a pity．

B：(5)________ a great party, Jack．

A：Thank you．Bye-bye．

B：Bye-bye．