阅读对话，从右边方框中选择适当的句子将对话补充完整。 Anna: Hello. Dr Smith’s office. John: Hello. 1 Anna: I’m afraid he isn’t here right now. I’m  Anna, Dr Smith’s assistant. 2 John: Yes, please. This is John. Dr Smith invited me to his daughter’s birthday party on Saturday night. 3 I have to go  to Australia on business this afternoon. I can’t come back until Sunday night. Anna: Oh, I’m very sorry to hear that. 4 John: Thank you. Goodbye. Anna: Goodbye. A. Hold on please. B. Can I take a message for you? C. I’ll give him the message. D. I’m afraid I may be a little late. E. I’m very sorry, but I can’t come. F. Could I speak to Dr Smith, please? G. Certainly.