口语运用。  从方框中选择恰当的句子补全对话。
A: Hello, Mike. What’s the time?
B: It’s half past eight.
A:    
B: Bob? He is at home.
A: Let’s go to the zoo with him.
B:I don’t think he can go to the zoo with us.
A:    
B: Because he has to look after his sister.
A:    
B: She is ill.
A:         Did she go to see a doctor?
B: Yes.
A:   
B: The doctor said there was nothing serious, but she has to rest in bed.

A. Why can’t he come? B. I’m sorry to hear that. C. Where’s Bob? D. What did the doctor say? E. What’s wrong with his sister?