补全对话。

A．Happy birthday!

B．I will help you.

C．Sorry, mum. I can’t.

D．Who can help me?

E. She’s buying things for my birthday party.
Sam: Where’s your mum?
Jack: She’s at the supermarket. (1)______________
Sam: Can I come to your birthday party?
Jack: Of course, you can.
Mum: I can’t carry the bags. (2)______________
Jack: (3)______________ I’m making a birthday card.
Sam: (4)______________
Mum: Thank you, Sam. Oh no, all the balloons are flying away.
Sam: But look at the sky. It says “(5)______________”