根据对话内容，在每上题的空白处填入适当的话语，使对话意思完整。

A: Hello! May I speak to Helen, please?

B: Sorry, ___________________________ 1. Who's that?

A: Oh, this is Peter speaking. Is that Mrs. Black?

B: Yes.

A: You know I've got something important to tell her. _____________________________2

B: Certainly.

A: Please tell her the students in our class are going to plant trees this Saturday.

B: ____________________________3?

A: We'll meet at the school gate at half past seven that morning.

B: ____________________________4?

A: No, that's all. Thank you, Mrs. Black.

B: ____________________________5. Bye.

A: Bye.