联系上下文填空完成对话。

Fang Fang: Mum, may I _____________ to Shanghai?

Mum: To Shanghai? I don't know.

Fang Fang: Shanghai is very beautiful.

Mum: But we live _____________ Changchun. Shanghai is _____________ _____________ here.

Fang Fang: You can come, _____________.

Mum: OK! You may go. But I _____________ go there.

Fang Fang: Why?

Mum: Because I have to work.

Fang Fang: Oh! I'm sorry to hear that.